U.S. patent application number 11/350172 was filed with the patent office on 2006-08-17 for protected polycarbonate films having thermal and uv radiation stability, and method of making.
Invention is credited to Wolfgang P. Abele, Brian Carvill, Michael D. Healy, Kwan Hongladarom, Michael M. Laurin.
Application Number | 20060182984 11/350172 |
Document ID | / |
Family ID | 36816006 |
Filed Date | 2006-08-17 |
United States Patent
Application |
20060182984 |
Kind Code |
A1 |
Abele; Wolfgang P. ; et
al. |
August 17, 2006 |
Protected polycarbonate films having thermal and UV radiation
stability, and method of making
Abstract
A composite film is disclosed, comprising a protective layer
comprising an adhesion-modified polyolefin film, a coating layer
comprising the reaction product of a crosslinkable compound, an
initiator, and a binder; and a polycarbonate layer; wherein the
coating layer is disposed between the protective layer and the
polycarbonate layer, and the peel strength between the protective
layer and the polycarbonate layer, as measured both before and
after thermal treatment or a combination of thermal and UV
treatment of the composite film, is about 1 to about 20
centi-Newtons per centimeter measured using 180.degree. angle peel
measured at a peel rate of 25.4 cm/min. A method for forming a
composite film, and an article comprising the composite film, are
also disclosed.
Inventors: |
Abele; Wolfgang P.;
(Newburgh, IN) ; Carvill; Brian; (Grayslake,
IL) ; Healy; Michael D.; (Evansville, IN) ;
Hongladarom; Kwan; (Mt. Vernon, IN) ; Laurin; Michael
M.; (Pittsfield, MA) |
Correspondence
Address: |
CANTOR COLBURN, LLP
55 GRIFFIN ROAD SOUTH
BLOOMFIELD
CT
06002
US
|
Family ID: |
36816006 |
Appl. No.: |
11/350172 |
Filed: |
February 8, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60653781 |
Feb 17, 2005 |
|
|
|
Current U.S.
Class: |
428/500 |
Current CPC
Class: |
B32B 2307/71 20130101;
Y10T 428/31855 20150401; B32B 27/36 20130101; B32B 2255/10
20130101; B32B 2255/26 20130101; B32B 27/32 20130101; B32B 27/365
20130101; B32B 2307/714 20130101; B32B 2559/00 20130101; B32B
2250/24 20130101; B32B 27/08 20130101 |
Class at
Publication: |
428/500 |
International
Class: |
B32B 27/00 20060101
B32B027/00 |
Claims
1. A composite film comprising a protective layer comprising an
adhesion-modified polyolefin film; a coating layer comprising the
reaction product of a crosslinkable compound, an initiator, and a
binder; and a polycarbonate layer; wherein the coating layer is
disposed between the protective layer and the polycarbonate layer,
and wherein the peel strength between the protective layer and the
polycarbonate layer, as measured both before and after thermal
treatment or a combination of thermal and UV treatment of the
composite film, is about 1 to about 20 centi-Newtons per centimeter
measured using 180.degree. angle peel measured at a peel rate of
25.4 cm/min.
2. The composite film of claim 1, wherein the adhesion-modified
polyolefin comprises a copolymer of a C.sub.2-18 olefin and an
adhesion-promoting monomer.
3. The composite film of claim 2, wherein the adhesion-promoting
monomer is an ethylenically unsaturated ester.
4. The composite film of claim 3 wherein the adhesion-modified
polyolefin comprises an adhesion-modified polyethylene.
5. The composite film of claim 1, wherein the crosslinkable
compound comprises one or more polyfunctional (meth)acryloyl
compounds.
6. The composite film of claim 1 wherein the initiator is a
photoinitiator, a chemical initiator, thermal initiator, or a
combination comprising at least one of the foregoing
initiators.
7. The composite film of claim 1 wherein the binder is a modified
polysaccharide, modified cellulose, or a combination of these.
8. The composite film of claim 1 wherein the polycarbonate layer
comprises bisphenol-A polycarbonate.
9. The composite film of claim 1 wherein the protective layer
further comprises a second film disposed on a surface of the
adhesion modified polyolefin film opposite the coating layer.
10. The composite film of claim 9 wherein the second film comprises
an unmodified polyolefin.
11. The composite film of claim 10 wherein the adhesion modified
polyolefin film and second film are coextruded.
12. The composite film of claim 1 wherein a second protective layer
is adhered to the face of the polycarbonate film opposite the
coating layer.
13. The composite film of claim 1 wherein the thermal treatment
comprises exposure to about 90.degree. C. for greater than or equal
to about 4 minutes.
14. The composite film of claim 1 wherein the UV treatement
comprises exposure of the composite film to ultraviolet radiation
at a wavelength of about 290 to about 405 nm, and at a dose of
greater than or equal to about 500, millijoules per square
centimeter.
15. A composite film comprising a protective layer comprising an
adhesion-modified polyolefin film; a coating layer comprising the
reaction product of a crosslinkable compound, an initiator, and a
binder; and a polycarbonate layer; wherein the coating layer is
disposed between the protective layer and the polycarbonate layer,
and the peel strength between the protective layer and the
polycarbonate layer, as measured both before and after thermal
treatment or a combination of thermal and UV treatment of the
composite film, is about 1 to about 20 centi-Newtons per centimeter
measured using 180.degree. angle peel measured at a peel rate of
25.4 cm/min, and wherein the thermal treatment comprises exposure
to about 90.degree. C. for greater than or equal to about 4
minutes, and wherein the UV treatement comprises exposure of the
composite film to ultraviolet radiation at a wavelength of about
290 to about 405 nm, and at a dose of greater than or equal to
about 500 millijoules per square centimeter.
16. A method of forming a composite film comprising curing a
coating composition comprising a crosslinkable compound, an
initiator, and a binder, wherein the coating composition is
disposed between a protective film comprising an adhesion modified
polyolefin, and a polycarbonate film, wherein the composite film
has a peel strength between the protective layer and the coating
layer, as measured both before and after thermal treatment or a
combination of thermal and UV treatment of the composite film, of
about 1 to about 20 centi-Newtons per centimeter measured using
180.degree. angle peel pull at a peel rate of 25.4 cm/min.
17. The method of claim 16 wherein the coating composition is
partially cured prior to disposing between the protective film and
the polycarbonate film.
18. The method of claim 16, wherein the curing is by laminating,
rolling, pressing, heating, exposing to radiation, or a combination
of one or more of these.
19. The composite film formed by the method of claim 16.
20. An article comprising the composite film of claim 1.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 60/653,781, filed Feb. 17, 2005, which is
incorporated herein by reference.
BACKGROUND
[0002] This disclosure relates to composite films comprising
polycarbonates having a protective layer laminated thereto, methods
of manufacture, and uses thereof.
[0003] Releasably masked substrates are useful for applications
where the masked substrate may be subject to processing operations
such as cutting, rolling, collating, folding, curing, exposure to
light, UV radiation, heat, pressure, and other stresses. In use,
the substrate has a protective layer ("mask") applied over one or
both faces, where the protective layer has properties such as
mechanical toughness, abrasion resistance, and chemical or solvent
resistance. The presence of the protective layer is useful in
minimizing damage to the masked polymer film from dust, particles
from processing, light, heat, moisture, solvents, inks, toners,
contaminants and other chemicals. Polyolefins, particularly
polyethylene ("PE") has been shown to be a useful protective
layer.
[0004] Specific applications where the substrate to be protected is
a transparent polymer film include printing applications of text or
designs, wherein a pattern is applied to the transparent polymer
film, cured to form a stable pattern, and the patterned film is
subsequently applied to a smooth surface such as metal, painted
surfaces, or glass. A polymer suitable for use in a transparent
film is polycarbonate ("PC"). In the curing of the pattern, the
transparent polymer film coated with a printed pattern is subject
to heat and/or ultraviolet (UV) radiation to effect cross-linking
of the ink, which may also affect the adhesion of previously
applied protective layers. Although masked PC substrates using
various commercially available protective PE films are presently
available, these materials typically have low initial and/or
post-processing adhesive levels. This can result in delamination,
subsequent product damage or contamination, processing yield
losses, and product quality degradation as these materials are
patterned, handled, and processed. Adhesive levels can also be too
high, either initially or post-processing, and may manifest as
productivity losses due to material damage, low quality yields,
film distortion, and the like. Excessive adhesion between layers
can also result in deposits of protective layer remaining on the
surface of the substrate, necessitating extra processing steps to
remove the PE masking from the PC substrate upon end use of an
article prepared from the masked substrate.
[0005] There accordingly remains a need in the art for a removable
protective layer for polycarbonate film substrates having a useful
level of adhesion between the protective layer and the
polycarbonate substrate layer throughout subsequent manufacturing
processes. Specifically, the adhesion properties of the protective
layer need retain a useful value after repeated exposure to heat
and/or UV radiation from subsequent manufacturing processes, while
allowing for facile removal of the protective layer.
SUMMARY OF THE INVENTION
[0006] The above-described and other deficiencies of the art are
met by a composite film comprising: a protective layer comprising
an adhesion-modified polyolefin film, a coating layer comprising
the reaction product of a crosslinkable compound, an initiator, and
a binder; and a polycarbonate layer; wherein the coating layer is
disposed between the protective layer and the polycarbonate layer,
and the peel strength between the protective layer and the
polycarbonate layer, as measured both before and after thermal
treatment or a combination of thermal and UV treatment of the
composite film, is about 1 to about 20 centi-Newtons per centimeter
measured using 180.degree. angle peel measured at a peel rate of
25.4 cm/min.
[0007] In another embodiment, a composite film comprises a
protective layer comprising an adhesion-modified polyolefin film; a
coating layer comprising the reaction product of a crosslinkable
compound, an initiator, and a binder; and a polycarbonate layer,
wherein the coating layer is disposed between the protective layer
and the polycarbonate layer, and the peel strength between the
protective layer and the polycarbonate layer, as measured both
before and after thermal treatment or a combination of thermal and
UV treatment of the composite film, is about 1 to about 20
centi-Newtons per centimeter measured using 180.degree. angle peel
measured at a peel rate of 25.4 cm/min; wherein the thermal
treatment comprises exposure to about 90.degree. C. for greater
than or equal to about 4 minutes, and wherein the UV treatement
comprises exposure of the composite film to ultraviolet radiation
at a wavelength of about 290 to about 405 nm, and at a dose of
greater than or equal to about 500 millijoules per square
centimeter.
[0008] In another embodiment, a method of forming a composite film
comprises curing a coating composition comprising a crosslinkable
compound, an initiator, and a binder, wherein the coating
composition is disposed between a protective film comprising an
adhesion modified polyolefin, and a polycarbonate film, wherein the
composite film has a peel strength between the protective layer and
the coating layer, as measured both before and after thermal
treatment or a combination of thermal and UV treatment of the
composite film, of about 1 to about 20 centi-Newtons per centimeter
measured using 180.degree. angle peel pull at a peel rate of 25.4
cm/min.
[0009] In another aspect, an article comprising the composite film
is disclosed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 shows a composite film having a single-layer
protective layer.
[0011] FIG. 2 shows a composite film having a two-layer protective
layer.
DETAILED DESCRIPTION
[0012] Composite films comprising a protective layer, a substrate
layer, and a coating layer disposed therebetween are disclosed,
wherein the adhesion between the protective layer and the adjacent
layers in the substrate remains suitable for the intended
application during and after exposure to conditions similar to
those encountered during manufacturing processes. The substrate
film specifically comprises a polycarbonate and a coating layer,
which is suited to applications of the composite film to printing,
digital imaging, and other image transfer applications.
[0013] The thermoplastic composition comprises a copolymer
comprising a polycarbonate. As used herein, the terms
"polycarbonate" and "polycarbonate resin" mean compositions having
repeating structural carbonate units of the formula (1): ##STR1##
in which greater than or equal to about 60 percent of the total
number of R.sup.1 groups are aromatic organic radicals and the
balance thereof are aliphatic, alicyclic, or aromatic radicals. In
an embodiment, each R.sup.1 is an aromatic organic radical. In
another embodiment, each R.sup.1 is a radical of the formula (2):
-A.sup.1-Y.sup.1-A.sup.2- (2) wherein each of A.sup.1 and A.sup.2
is a monocyclic divalent aryl radical and Y.sup.1 is a bridging
radical having one or two atoms that separate A.sup.1 from A.sup.2.
In an exemplary embodiment, one atom separates A.sup.1 from
A.sup.2. Illustrative non-limiting examples of radicals of this
type are --O--, --S--, --S(O)--, --S(O).sub.2--, --C(O)--,
methylene, cyclohexylmethylene, 2-[2.2.1]-bicycloheptylidene,
ethylidene, isopropylidene, neopentylidene, cyclohexylidene,
cyclopentadecylidene, cyclododecylidene, and adamantylidene. The
bridging radical Y.sup.1 may be a hydrocarbon group or a saturated
hydrocarbon group such as methylene, cyclohexylidene, or
isopropylidene. In another embodiment, Y.sup.1 is a carbon-carbon
bond (--) connecting A.sup.1 and A.sup.2.
[0014] Polycarbonates may be produced by the interfacial reaction
of dihydroxy compounds having the formula HO--R.sup.1--OH, which
includes dihydroxy aromatic compounds of formula (3):
HO-A.sup.1-Y.sup.1-A.sup.2-OH (3) wherein Y.sup.1, A.sup.1 and
A.sup.2 are as described above. Also included are bisphenol
compounds of general formula (4): ##STR2## wherein R.sup.a and
R.sup.b each represent a halogen atom or a monovalent hydrocarbon
group and may be the same or different; p and q are each
independently integers of 0 to 4; and X.sup.a represents one of the
groups of formula (5): ##STR3## wherein R.sup.c and R.sup.d each
independently represent a hydrogen atom or a monovalent linear
alkyl or cyclic alkylene group and R.sup.e is a divalent
hydrocarbon group. In an embodiment, R.sup.c and R.sup.d represent
a cyclic alkylene group; or heteroatom-containing cyclic alkylene
group comprising carbon atoms, heteroatoms with a valency of two or
greater, or a combination comprising at least one heteroatom and at
least two carbon atoms. Suitable heteroatoms for use in the
heteroatom-containing cyclic alkylene group include --O--, --S--,
and --N(Z)-, where Z is a substituent group selected from hydrogen,
hydroxy, C.sub.1-12 alkyl, C.sub.1-12 alkoxy, or C.sub.1-12 acyl.
Where present, the cyclic alkylene group or heteroatom-containing
cyclic alkylene group may have 3 to 20 atoms, and may be a single
saturated or unsaturated ring, or fused polycyclic ring system
wherein the fused rings are saturated, unsaturated, or
aromatic.
[0015] Some illustrative, non-limiting examples of suitable
dihydroxy compounds include the following: 4,4'-dihydroxybiphenyl,
1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene,
bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)diphenylmethane,
bis(4-hydroxyphenyl)-1-naphthylmethane,
1,2-bis(4-hydroxyphenyl)ethane,
1,1-bis(4-hydroxyphenyl)-1-phenylethane,
2-(4-hydroxyphenyl)-2-(3-hydroxyphenyl)propane,
bis(4-hydroxyphenyl)phenylmethane,
2,2-bis(4-hydroxy-3-bromophenyl)propane,
1,1-bis(hydroxyphenyl)cyclopentane,
1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxy-3 methyl
phenyl)cyclohexane 1,1-bis(4-hydroxyphenyl)isobutene,
1,1-bis(4-hydroxyphenyl)cyclododecane,
trans-2,3-bis(4-hydroxyphenyl)-2-butene,
2,2-bis(4-hydroxyphenyl)adamantine, (alpha,
alpha'-bis(4-hydroxyphenyl)toluene,
bis(4-hydroxyphenyl)acetonitrile,
2,2-bis(3-methyl-4-hydroxyphenyl)propane,
2,2-bis(3-ethyl-4-hydroxyphenyl)propane,
2,2-bis(3-n-propyl-4-hydroxyphenyl)propane,
2,2-bis(3-isopropyl-4-hydroxyphenyl)propane,
2,2-bis(3-sec-butyl-4-hydroxyphenyl)propane,
2,2-bis(3-t-butyl-4-hydroxyphenyl)propane,
2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane,
2,2-bis(3-allyl-4-hydroxyphenyl)propane,
2,2-bis(3-methoxy-4-hydroxyphenyl)propane,
2,2-bis(4-hydroxyphenyl)hexafluoropropane,
1,1-dichloro-2,2-bis(4-hydroxyphenyl)ethylene,
1,1-dibromo-2,2-bis(4-hydroxyphenyl)ethylene,
1,1-dichloro-2,2-bis(5-phenoxy-4-hydroxyphenyl)ethylene,
4,4'-dihydroxybenzophenone, 3,3-bis(4-hydroxyphenyl)-2-butanone,
1,6-bis(4-hydroxyphenyl)-1,6-hexanedione, ethylene glycol
bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)ether,
bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)sulfoxide,
bis(4-hydroxyphenyl)sulfone, 9,9-bis(4-hydroxyphenyl)fluorine,
2,7-dihydroxypyrene,
6,6'-dihydroxy-3,3,3',3'-tetramethylspiro(bis)indane
("spirobiindane bisphenol"), 3,3-bis(4-hydroxyphenyl)phthalide,
2,6-dihydroxydibenzo-p-dioxin, 2,6-dihydroxythianthrene,
2,7-dihydroxyphenoxathin, 2,7-dihydroxy-9,10-dimethylphenazine,
3,6-dihydroxydibenzofuran, 3,6-dihydroxydibenzothiophene, and
2,7-dihydroxycarbazole, and the like, as well as combinations
comprising at least one of the foregoing dihydroxy compounds.
[0016] Specific examples of the types of bisphenol compounds
represented by formula (3) include 1,1-bis(4-hydroxyphenyl)methane,
1,1-bis(4-hydroxyphenyl) ethane, 2,2-bis(4-hydroxyphenyl)propane
(hereinafter "bisphenol A" or "BPA"),
2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane,
1,1-bis(4-hydroxyphenyl) propane, 1,1-bis(4-hydroxyphenyl)
n-butane, 2,2-bis(4-hydroxy-1-methylphenyl) propane,
1,1-bis(4-hydroxy-t-butylphenyl)propane,
3,3-bis(4-hydroxyphenyl)phthalimidine,
2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine (PPPBP), and
1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane (DMBPC). Combinations
comprising at least one of the foregoing dihydroxy compounds may
also be used.
[0017] Suitable polycarbonates further include those derived from
bisphenols containing alkyl cyclohexane units. Such bisphenols have
structural units corresponding to the formula (6): ##STR4## wherein
R.sup.a-R.sup.d are each independently hydrogen, C.sub.1-12 alkyl,
or halogen; and substituents R.sub.e-R.sub.i and R.sub.e'-R.sub.i'
are each independently hydrogen or C.sub.1-12 alkyl. The
substituents may be aliphatic or aromatic, straight-chain, cyclic,
bicyclic, branched, saturated, or unsaturated. In a specific
embodiment, alkyl cyclohexane-containing bisphenols, for example
the reaction product of two moles of a phenol with one mole of a
hydrogenated isophorone, are useful for making polycarbonate
polymers with high glass transition temperatures and high heat
distortion temperatures. Such isophorone bisphenol-containing
polycarbonates correspond to formula (6), wherein each of R.sub.f,
R.sub.f', and R.sub.h are methyl groups; R.sub.e, R.sub.e',
R.sub.g, R.sub.g', R.sub.h', R.sub.i, and R.sub.i' are each
hydrogen; and R.sub.a-R.sub.d are as defined above. These
isophorone bisphenol based polymers, including polycarbonate
copolymers made containing non-alkyl cyclohexane bisphenols and
blends of alkyl cyclohexyl bisphenol containing polycarbonates with
non-alkyl cyclohexyl bisphenol polycarbonates, are supplied by
Bayer Co. under the APEC.RTM. trade name.
[0018] Another dihydroxy aromatic group R.sup.1 is derived from a
dihydroxy aromatic compound of formula (7): ##STR5## wherein each
R.sup.f is independently a halogen atom, a C.sub.1-12 hydrocarbon
group, or a C.sub.1-12 halogen substituted hydrocarbon group, and p
is 0 to 4. The halogen is usually bromine. Examples of compounds
that may be represented by the formula (7) include resorcinol,
substituted resorcinol compounds such as 5-methyl resorcinol,
5-ethyl resorcinol, 5-propyl resorcinol, 5-butyl resorcinol,
5-t-butyl resorcinol, 5-phenyl resorcinol, 5-cumyl resorcinol,
2,4,5,6-tetrafluoro resorcinol, 2,4,5,6-tetrabromo resorcinol, or
the like; catechol; hydroquinone; substituted hydroquinones such as
2-methyl hydroquinone, 2-ethyl hydroquinone, 2-propyl hydroquinone,
2-butyl hydroquinone, 2-t-butyl hydroquinone, 2-phenyl
hydroquinone, 2-cumyl hydroquinone, 2,3,5,6-tetramethyl
hydroquinone, 2,3,5,6-tetra-t-butyl hydroquinone,
2,3,5,6-tetrafluoro hydroquinone, 2,3,5,6-tetrabromo hydroquinone,
or the like; or a combination comprising at least one of the
foregoing compounds.
[0019] Branched polycarbonates are also useful, as well as blends
of a linear polycarbonate and a branched polycarbonate. The
branched polycarbonates may be prepared by adding a branching agent
during polymerization. These branching agents include
polyfunctional organic compounds containing at least three
functional groups selected from hydroxyl, carboxyl, carboxylic
anhydride, haloformyl, and combinations of the foregoing functional
groups. Specific examples include trimellitic acid, trimellitic
anhydride, trimellitic trichloride, tris-p-hydroxy phenyl ethane,
isatin-bis-phenol, tris-phenol TC
(1,3,5-tris((p-hydroxyphenyl)isopropyl)benzene), tris-phenol PA
(4(4(1,1-bis(p-hydroxyphenyl)-ethyl) alpha, alpha-dimethyl
benzyl)phenol), 4-chloroformyl phthalic anhydride, trimesic acid,
and benzophenone tetracarboxylic acid. The branching agents may be
added at a level of about 0.05 to about 2.0 wt %. All types of
polycarbonate end groups are contemplated as being useful in the
polycarbonate composition, provided that such end groups do not
significantly affect desired properties of the thermoplastic
compositions.
[0020] In a specific embodiment, the polycarbonate is a linear
homopolymer derived from bisphenol A, in which each of A.sup.1 and
A.sup.2 is p-phenylene and Y.sup.1 is isopropylidene. The
polycarbonates may have an intrinsic viscosity, as determined in
chloroform at 25.degree. C., of about 0.3 to about 1.5 deciliters
per gram (dl/g), specifically about 0.45 to about 1.0 dl/g. The
polycarbonates may have a weight average molecular weight of about
10,000 to about 200,000, specifically about 20,000 to about
100,000, as measured by gel permeation chromatography.
[0021] In an embodiment, the polycarbonate has flow properties
suitable for the manufacture of thin articles. Melt volume flow
rate (often abbreviated MVR) measures the rate of extrusion of a
thermoplastics through an orifice at a prescribed temperature and
load. Polycarbonates suitable for the formation of thin articles
may have an MVR, measured at 300.degree. C. under a load of 1.2 kg
according to ASTM D1238-04, of about 0.4 to about 25 cubic
centimeters per 10 minutes (cc/10 min), specifically about 5 to
about 9 cc/10/min. Combinations of polycarbonates of different flow
properties may be used to achieve the overall desired flow
property.
[0022] The polycarbonate may have a light transmittance greater
than or equal to 55%, specifically greater than or equal to 60% and
more specifically greater than or equal to 70%, as measured at 3.2
millimeters thickness according to ASTM D1003-00. The polycarbonate
may also have a haze less than or equal to 50%, specifically less
than or equal to 40%, and most specifically less than or equal to
30%, as measured at 3.2 millimeters thickness according to ASTM
D1003-00.
[0023] "Polycarbonates" and "polycarbonate resins" as used herein
further include, in addition to homopolycarbonates, copolymers
comprising different R.sup.1 moieties in the carbonate (referred to
herein as "copolycarbonates"), copolymers comprising carbonate
units and other types of polymer units, such as ester units, and
combinations comprising one or more of homopolycarbonates and
copolycarbonates. As used herein, "combination" is inclusive of
blends, mixtures, alloys, reaction products, and the like.
[0024] A specific suitable copolymer is a polyester carbonate, also
known as a copolyester-polycarbonate and polyester-polycarbonate.
Such copolymers further contain, in addition to recurring carbonate
chain units of the formula (1), repeating units of formula (8):
##STR6## wherein D is a divalent radical derived from a dihydroxy
compound, and may be, for example, a C.sub.2-10 alkylene radical, a
C.sub.6-20 alicyclic radical, a C.sub.6-20 aromatic radical or a
polyoxyalkylene radical in which the alkylene groups contain 2 to
about 6 carbon atoms, specifically 2, 3, or 4 carbon atoms; and T
divalent radical derived from a dicarboxylic acid, and may be, for
example, a C.sub.2-10 alkylene radical, a C.sub.6-20 alicyclic
radical, a C.sub.6-20 alkyl aromatic radical, or a C.sub.6-20
aromatic radical.
[0025] In one embodiment, D is a C.sub.2-6 alkylene radical. In
another embodiment, D is derived from an aromatic dihydroxy
compound of formula (4) above. In another embodiment, D is derived
from an aromatic dihydroxy compound of formula (7) above.
[0026] Examples of aromatic dicarboxylic acids that may be used to
prepare the polyesters include isophthalic or terephthalic acid,
1,2-di(p-carboxyphenyl)ethane, 4,4'-dicarboxydiphenyl ether,
4,4'-bisbenzoic acid, and combinations comprising at least one of
the foregoing acids. Acids containing fused rings can also be
present, such as in 1,4-, 1,5-, or 2,6-naphthalenedicarboxylic
acids. Specific dicarboxylic acids are terephthalic acid,
isophthalic acid, naphthalene dicarboxylic acid, cyclohexane
dicarboxylic acid, or combinations thereof. A specific dicarboxylic
acid comprises a combination of isophthalic acid and terephthalic
acid wherein the weight ratio of terephthalic acid to isophthalic
acid is about 99:1 to about 1:99. In another specific embodiment, D
is a C.sub.2-6 alkylene radical and T is p-phenylene, m-phenylene,
naphthalene, a divalent cycloaliphatic radical, or a combination
thereof. This class of polyester includes the poly(alkylene
terephthalates).
[0027] The polyester-polycarbonates may have a weight-averaged
molecular weight (Mw) of 1,500 to 100,000, specifically 1,700 to
50,000, and more specifically 2,000 to 40,000. Molecular weight
determinations are performed using gel permeation chromatography
(GPC), using a crosslinked styrene-divinylbenzene column and
calibrated to BPA-polycarbonate references. Samples are prepared at
a concentration of about 1 mg/ml, and are eluted at a flow rate of
about 1.0 ml/min.
[0028] Suitable polycarbonates can be manufactured by processes
such as interfacial polymerization and melt polymerization.
Although the reaction conditions for interfacial polymerization may
vary, an exemplary process generally involves dissolving or
dispersing a dihydric phenol reactant in aqueous caustic soda or
potash, adding the resulting mixture to a suitable water-immiscible
solvent medium, and contacting the reactants with a carbonate
precursor in the presence of a suitable catalyst such as
triethylamine or a phase transfer catalyst, under controlled pH
conditions, e.g., about 8 to about 10. The most commonly used water
immiscible solvents include methylene chloride, 1,2-dichloroethane,
chlorobenzene, toluene, and the like. Suitable carbonate precursors
include, for example, a carbonyl halide such as carbonyl bromide or
carbonyl chloride (phosgene), or a haloformate such as a
bishaloformates of a dihydric phenol (e.g., the bischloroformates
of bisphenol A, hydroquinone, or the like) or a glycol (e.g., the
bishaloformate of ethylene glycol, neopentyl glycol, polyethylene
glycol, or the like). Combinations comprising at least one of the
foregoing types of carbonate precursors may also be used. In an
exemplary embodiment, an interfacial polymerization to form
carbonate linkages uses phosgene, and is referred to as a
phosgenation reaction.
[0029] Among the phase transfer catalysts that may be used are
catalysts of the formula (R.sup.3).sub.4Q.sup.+X, wherein each
R.sup.3 is the same or different, and is a C.sub.1-10 alkyl group;
Q is a nitrogen or phosphorus atom; and X is a halogen atom or a
C.sub.1-8 alkoxy group or C.sub.6-18 aryloxy group. Suitable phase
transfer catalysts include, for example,
[CH.sub.3(CH.sub.2).sub.3].sub.4NX,
[CH.sub.3(CH.sub.2).sub.3].sub.4PX,
[CH.sub.3(CH.sub.2).sub.5].sub.4NX,
[CH.sub.3(CH.sub.2).sub.6].sub.4NX,
[CH.sub.3(CH.sub.2).sub.4].sub.4NX,
CH.sub.3[CH.sub.3(CH.sub.2).sub.3].sub.3NX, and
CH.sub.3[CH.sub.3(CH.sub.2).sub.2].sub.3NX, wherein X is Cl.sup.-,
Br.sup.-, a C.sub.1-8 alkoxy group or a C.sub.6-18 aryloxy group.
An effective amount of a phase transfer catalyst may be about 0.1
to about 10 wt % based on the weight of bisphenol in the
phosgenation mixture. In another embodiment an effective amount of
phase transfer catalyst may be about 0.5 to about 2 wt % based on
the weight of bisphenol in the phosgenation mixture.
[0030] A chain stopper (also referred to as a capping agent) may be
included during polymerization. The chain-stopper limits molecular
weight growth rate, and so controls molecular weight in the
polycarbonate. Exemplary chain-stoppers include certain
mono-phenolic compounds, mono-carboxylic acid chlorides, and/or
mono-chloroformates. Suitable mono-phenolic chain stoppers are
exemplified by monocyclic phenols such as phenol and
C.sub.1-C.sub.22 alkyl-substituted phenols such as p-cumyl-phenol,
resorcinol monobenzoate, and p- and tertiary-butyl phenol; and
monoethers of diphenols, such as p-methoxyphenol. Alkyl-substituted
phenols with branched chain alkyl substituents having 8 to 9 carbon
atom may be specifically mentioned. Certain mono-phenolic UV
absorbers may also be used as a capping agent, for example
4-substituted-2-hydroxybenzophenones and their derivatives, aryl
salicylates, monoesters of diphenols such as resorcinol
monobenzoate, 2-(2-hydroxyaryl)-benzotriazoles and their
derivatives, 2-(2-hydroxyaryl)-1,3,5-triazines and their
derivatives, and the like.
[0031] Mono-carboxylic acid chlorides may also be used as chain
stoppers. These include monocyclic, mono-carboxylic acid chlorides
such as benzoyl chloride, C.sub.1-C.sub.22 alkyl-substituted
benzoyl chloride, toluoyl chloride, halogen-substituted benzoyl
chloride, bromobenzoyl chloride, cinnamoyl chloride,
4-nadimidobenzoyl chloride, and mixtures thereof; polycyclic,
mono-carboxylic acid chlorides such as trimellitic anhydride
chloride, and naphthoyl chloride; and mixtures of monocyclic and
polycyclic mono-carboxylic acid chlorides. Chlorides of aliphatic
monocarboxylic acids with up to 22 carbon atoms are suitable.
Functionalized chlorides of aliphatic monocarboxylic acids, such as
acryloyl chloride and methacryoyl chloride, are also suitable. Also
suitable are mono-chloroformates including monocyclic,
mono-chloroformates, such as phenyl chloroformate,
alkyl-substituted phenyl chloroformate, p-cumyl phenyl
chloroformate, toluene chloroformate, and mixtures thereof.
[0032] Alternatively, melt processes may be used to make
polycarbonates or polycarbonate blocks. Generally, in the melt
polymerization process, polycarbonates may be prepared by
co-reacting, in a molten state, the dihydroxy reactant(s) and a
diaryl carbonate ester, such as diphenyl carbonate, in the presence
of a transesterification catalyst in a Banbury.RTM. mixer, twin
screw extruder, or the like to form a uniform dispersion. Volatile
monohydric phenol is removed from the molten reactants by
distillation and the polymer is isolated as a molten residue. A
specifically useful melt process for making polycarbonates uses, a
diaryl carbonate ester having electron withdrawing substituents on
the aryls. Examples of specifically useful diaryl carbonate esters
with electron withdrawing substituents include
bis(4-nitrophenyl)carbonate, bis(2-chlorophenyl)carbonate,
bis(4-chlorophenyl)carbonate, bis(methyl salicyl)carbonate (BMSC),
bis(4-methylcarboxylphenyl)carbonate, bis(2-acetylphenyl)
carboxylate, bis(4-acetylphenyl)carboxylate, or a combination
comprising at least one of these. In addition, suitable
transesterification catalyst for use may include phase transfer
catalysts of formula (R.sup.3).sub.4Q.sup.+X above, wherein each
R.sup.3, Q, and X are as defined above. Examples of suitable
transesterification catalysts include tetrabutylammonium hydroxide,
methyltributylammonium hydroxide, tetrabutylammonium acetate,
tetrabutylphosphonium hydroxide, tetrabutylphosphonium acetate,
tetrabutylphosphonium phenolate, or a combination comprising at
least one of these.
[0033] The polyester-polycarbonate resins may also be prepared by
interfacial polymerization. Rather than utilizing the dicarboxylic
acid per se, it is desirable to use the reactive derivatives of the
acid, such as the corresponding acid halides, specifically the acid
dichlorides and the acid dibromides. Thus, for example instead of
using isophthalic acid, terephthalic acid, or combinations thereof,
it is possible to employ isophthaloyl dichloride, terephthaloyl
dichloride, and combinations thereof.
[0034] In addition to the polycarbonates described above, it is
also possible to use combinations of the polycarbonate with other
thermoplastic polymers, for example combinations of polycarbonates
and/or polycarbonate copolymers with polyesters. Suitable
polyesters comprise repeating units of formula (8), and may be, for
example, poly(alkylene dicarboxylates), liquid crystalline
polyesters, and polyester copolymers. It is also possible to use a
branched polyester in which a branching agent, for example, a
glycol having three or more hydroxyl groups or a trifunctional or
multifunctional carboxylic acid has been incorporated. Furthermore,
it is sometime desirable to have various concentrations of acid and
hydroxyl end groups on the polyester, depending on the ultimate end
use of the composition.
[0035] In an embodiment, poly(alkylene terephthalate)s are used.
Specific examples of suitable poly(alkylene terephthalates) are
poly(ethylene terephthalate) (PET), poly(1,4-butylene
terephthalate) (PBT), poly(ethylene naphthanoate) (PEN),
poly(butylene naphthanoate), (PBN), (polypropylene terephthalate)
(PPT), polycyclohexanedimethanol terephthalate (PCT), and
combinations comprising at least one of the foregoing polyesters.
Another polyester which can be used is the saturated
poly(1,4-cyclohexanedimethylene 1,4-cyclohexanedicarboxylate)
(PCCD). Polyester copolymers may include poly(ethylene
terephthalate)-co-(1,4-cyclohexanedimethylene terephthalate),
abbreviated as PETG where the polymer comprises greater than or
equal to 50 mol % of ethylene terephthalate ester units, and
abbreviated as PCTG where the polymer comprises greater than 50 mol
% of 1,4-cyclohexanedimethylene terephthalate ester units. Also
contemplated are the above polyesters with a minor amount, e.g.,
from about 0.5 to about 10 percent by weight, of units derived from
an aliphatic diacid and/or an aliphatic polyol to make
copolyesters.
[0036] The blends of a polycarbonate and a polyester may comprise
about 1 to about 99 wt % polycarbonate and correspondingly about 99
to about 1 wt % polyester, in particular a poly(alkylene
terephthalate). In an embodiment, the blend comprises about 30 to
about 70 wt % polycarbonate and correspondingly about 70 to about
30 wt % polyester. The foregoing amounts are base on the total
weight of the polycarbonate resin and polyester resin.
[0037] The composition may further comprises a
polysiloxane-polycarbonate copolymer. The polydiorganosiloxane
blocks of the copolymer comprise repeating polydiorganosiloxane
units of formula (9): ##STR7## wherein each occurrence of R is same
or different, and is a C.sub.1-13 monovalent organic radical. For
example, R may be a C.sub.1-C.sub.13 alkyl group, C.sub.1-C.sub.13
alkoxy group, C.sub.2-C.sub.13 alkenyl group, C.sub.2-C.sub.13
alkenyloxy group, C.sub.3-C.sub.6 cycloalkyl group, C.sub.3-C.sub.6
cycloalkoxy group, C.sub.6-C.sub.14 aryl group, C.sub.6-C.sub.10
aryloxy group, C.sub.7-C.sub.13 aralkyl group, C.sub.7-C.sub.13
aralkoxy group, C.sub.7-C.sub.13 alkaryl group, or C.sub.7-C.sub.13
alkaryloxy group. The foregoing groups may be fully or partially
halogenated with fluorine, chlorine, bromine, or iodine, or a
combination thereof. Combinations of the foregoing R groups may be
used in the same copolymer.
[0038] The value of E in formula (9) may vary widely depending on
the type and relative amount of each component in the thermoplastic
composition, the desired properties of the composition, and like
considerations. Generally, E may have an average value of 2 to
about 1,000, specifically about 2 to about 500, more specifically
about 5 to about 100. In an embodiment, E has an average value of
about 10 to about 75, and in still another embodiment, E has an
average value of about 40 to about 60. Where E is of a lower value,
e.g., less than about 40, it may be desirable to use a relatively
larger amount of the polycarbonate-polysiloxane copolymer.
Conversely, where E is of a higher value, e.g., greater than about
40, it may be necessary to use a relatively lower amount of the
polycarbonate-polysiloxane copolymer.
[0039] A combination of a first and a second (or more)
polycarbonate-polysiloxane copolymers may be used, wherein the
average value of E of the first copolymer is less than the average
value of E of the second copolymer.
[0040] In an embodiment, the polydiorganosiloxane blocks are
provided by repeating structural units of formula (10): ##STR8##
wherein E is as defined above; each R may be the same or different,
and is as defined above; and Ar may be the same or different, and
is a substituted or unsubstituted C.sub.6-C.sub.30 arylene radical,
wherein the bonds are directly connected to an aromatic moiety.
Suitable Ar groups in formula (10) may be derived from a
C.sub.6-C.sub.30 dihydroxyarylene compound, for example a
dihydroxyarylene compound of formula (3), (4), or (7) above.
Combinations comprising at least one of the foregoing
dihydroxyarylene compounds may also be used. Specific examples of
suitable dihydroxyarlyene compounds are
1,1-bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane,
2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane,
2,2-bis(4-hydroxyphenyl) octane, 1,1-bis(4-hydroxyphenyl)propane,
1,1-bis(4-hydroxyphenyl) n-butane,
2,2-bis(4-hydroxy-1-methylphenyl)propane, 1,1-bis(4-hydroxyphenyl)
cyclohexane, bis(4-hydroxyphenyl sulphide), and
1,1-bis(4-hydroxy-t-butylphenyl) propane. Combinations comprising
at least one of the foregoing dihydroxy compounds may also be
used.
[0041] Such units may be derived from the corresponding dihydroxy
compound of formula (11): ##STR9## wherein Ar and E are as
described above. Such compounds are further described in U.S. Pat.
No. 4,746,701 to Kress et al. Compounds of formula (11) may be
obtained by the reaction of a dihydroxyarylene compound with, for
example, an alpha, omega-bisacetoxypolydiorangonosiloxane under
phase transfer conditions.
[0042] In another embodiment, polydiorganosiloxane blocks comprises
units of formula (12): ##STR10## wherein R is as described above, E
is 1 to 1,000, each occurrence of R.sup.1 is independently a
divalent C.sub.1-C.sub.30 organic radical, and wherein the
polymerized polysiloxane unit is the reaction residue of its
corresponding dihydroxy compound. In a specific embodiment, the
polydiorganosiloxane blocks are provided by repeating structural
units of formula (13): ##STR11## wherein R and E are as defined
above. R.sup.2 in formula (12) is a divalent C.sub.2-C.sub.8
aliphatic group. Each M in formula (12) may be the same or
different, and may be a halogen, cyano, nitro, C.sub.1-C.sub.8
alkylthio, C.sub.1-C.sub.8 alkyl, C.sub.1-C.sub.8 alkoxy,
C.sub.2-C.sub.8 alkenyl, C.sub.2-C.sub.8 alkenyloxy group,
C.sub.3-C.sub.8 cycloalkyl, C.sub.3-C.sub.8 cycloalkoxy,
C.sub.6-C.sub.10 aryl, C.sub.6-C.sub.10 aryloxy, C.sub.7-C.sub.12
aralkyl, C.sub.7-C.sub.12 aralkoxy, C.sub.7-C.sub.12 alkaryl, or
C.sub.7-C.sub.12 alkaryloxy, wherein each n is independently 0, 1,
2, 3, or 4.
[0043] In an embodiment, M is bromo or chloro, an alkyl group such
as methyl, ethyl, or propyl, an alkoxy group such as methoxy,
ethoxy, or propoxy, or an aryl group such as phenyl, chlorophenyl,
or tolyl; R.sup.2 is a dimethylene, trimethylene or tetramethylene
group; and R is a C.sub.1-8 alkyl, haloalkyl such as
trifluoropropyl, cyanoalkyl, or aryl such as phenyl, chlorophenyl
or tolyl. In another embodiment, R is methyl, or a combination of
methyl and trifluoropropyl, or a combination of methyl and phenyl.
In still another embodiment, M is methoxy, n is one, R is a
divalent C.sub.1-C.sub.3 aliphatic group, and R is methyl.
[0044] Units of formula (13) may be derived from the corresponding
dihydroxy polydiorganosiloxane (14): ##STR12## wherein R, E, M,
R.sup.2, and n are as described above. Such dihydroxy polysiloxanes
can be made by effecting a platinum catalyzed addition between a
siloxane hydride of formula (15): ##STR13## wherein R and E are as
previously defined, and an aliphatically unsaturated monohydric
phenol. Suitable aliphatically unsaturated monohydric phenols
included, for example, eugenol, 2-alkylphenol,
4-allyl-2-methylphenol, 4-allyl-2-phenylphenol,
4-allyl-2-bromophenol, 4-allyl-2-t-butoxyphenol,
4-phenyl-2-phenylphenol, 2-methyl-4-propylphenol,
2-allyl-4,6-dimethylphenol, 2-allyl-4-bromo-6-methylphenol,
2-allyl-6-methoxy-4-methylphenol and 2-allyl-4,6-dimethylphenol.
Combinations comprising at least one of the foregoing may also be
used.
[0045] The polycarbonate composition may further comprise a flame
retardant. Suitable flame retardants that may be added may be
organic compounds that include phosphorus, bromine, and/or
chlorine. Non-brominated and non-chlorinated phosphorus-containing
flame retardants may be preferred in certain applications for
regulatory reasons, for example organic phosphates and organic
compounds containing phosphorus-nitrogen bonds.
[0046] One type of exemplary organic phosphate is an aromatic
phosphate of the formula (GO).sub.3P.dbd.O, wherein each G is
independently an alkyl, cycloalkyl, aryl, alkylaryl, or arylalkyl
group, provided that at least one G is an aromatic group. Two of
the G groups may be joined together to provide a cyclic group, for
example, diphenyl pentaerythritol diphosphate. Other suitable
aromatic phosphates may be, for example, phenyl bis(dodecyl)
phosphate, phenyl bis(neopentyl) phosphate, phenyl
bis(3,5,5'-trimethylhexyl) phosphate, ethyl diphenyl phosphate,
2-ethylhexyl di(p-tolyl) phosphate, bis(2-ethylhexyl) p-tolyl
phosphate, tritolyl phosphate, bis(2-ethylhexyl) phenyl phosphate,
tri(nonylphenyl) phosphate, bis(dodecyl) p-tolyl phosphate, dibutyl
phenyl phosphate, 2-chloroethyl diphenyl phosphate, p-tolyl
bis(2,5,5'-trimethylhexyl) phosphate, 2-ethylhexyl diphenyl
phosphate, or the like. A specific aromatic phosphate is one in
which each G is aromatic, for example, triphenyl phosphate,
tricresyl phosphate, isopropylated triphenyl phosphate, and the
like.
[0047] Di- or polyfunctional aromatic phosphorus-containing
compounds are also useful, for example, compounds of the formulas
below: ##STR14## wherein each G.sup.1 is independently a
hydrocarbon having 1 to 30 carbon atoms; each G.sup.2 is
independently a hydrocarbon or hydrocarbonoxy having 1 to 30 carbon
atoms; each X.sup.a is independently a hydrocarbon having 1 to 30
carbon atoms; each X is independently a bromine or chlorine; m is 0
to 4, and n is 1 to 30. Examples of suitable di- or polyfunctional
aromatic phosphorus-containing compounds include resorcinol
tetraphenyl diphosphate (RDP), the bis(diphenyl) phosphate of
hydroquinone and the bis(diphenyl) phosphate of bisphenol-A,
respectively, their oligomeric and polymeric counterparts, and the
like.
[0048] Exemplary suitable flame retardant compounds containing
phosphorus-nitrogen bonds include phosphonitrilic chloride,
phosphorus ester amides, phosphoric acid amides, phosphonic acid
amides, phosphinic acid amides, tris(aziridinyl) phosphine oxide.
When present, phosphorus-containing flame retardants can be present
in amounts of 0.1 to 10 percent by weight, based on the total
weight of the polycarbonate.
[0049] Halogenated materials may also be used as flame retardants,
for example halogenated compounds and resins of formula (16):
##STR15## wherein R is an alkylene, alkylidene or cycloaliphatic
linkage, e.g., methylene, ethylene, propylene, isopropylene,
isopropylidene, butylene, isobutylene, amylene, cyclohexylene,
cyclopentylidene, or the like; or an oxygen ether, carbonyl, amine,
or a sulfur containing linkage, e.g., sulfide, sulfoxide, sulfone,
or the like. R can also consist of two or more alkylene or
alkylidene linkages connected by such groups as aromatic, amino,
ether, carbonyl, sulfide, sulfoxide, sulfone, or the like.
[0050] Ar and Ar' in formula (16) are each independently mono- or
polycarbocyclic aromatic groups such as phenylene, biphenylene,
terphenylene, naphthylene, or the like.
[0051] Y is an organic, inorganic, or organometallic radical, for
example: halogen, e.g., chlorine, bromine, iodine, fluorine; ether
groups of the general formula OB, wherein B is a monovalent
hydrocarbon radical similar to X; monovalent hydrocarbon groups of
the type represented by R; or other substituents, e.g., nitro,
cyano, and the like, said substituents being essentially inert
provided that there is at least one and preferably two halogen
atoms per aryl nucleus.
[0052] When present, each X is independently a monovalent
hydrocarbon group, for example an alkyl group such as methyl,
ethyl, propyl, isopropyl, butyl, decyl, or the like; an aryl groups
such as phenyl, naphthyl, biphenyl, xylyl, tolyl, or the like; and
arylalkyl group such as benzyl, ethylphenyl, or the like; a
cycloaliphatic group such as cyclopentyl, cyclohexyl, or the like.
The monovalent hydrocarbon group may itself contain inert
substituents.
[0053] Each d is independently 1 to a maximum equivalent to the
number of replaceable hydrogens substituted on the aromatic rings
comprising Ar or Ar'. Each e is independently 0 to a maximum
equivalent to the number of replaceable hydrogens on R. Each a, b,
and c is independently a whole number, including 0. When b is not
0, neither a nor c may be 0. Otherwise either a or c, but not both,
may be 0. Where b is 0, the aromatic groups are joined by a direct
carbon-carbon bond.
[0054] Hydroxyl and Y substituents on the aromatic groups, Ar and
Ar', can be varied in the ortho, meta or para positions on the
aromatic rings and the groups can be in any possible geometric
relationship with respect to one another.
[0055] Included within the scope of the above formula are
bisphenols of which the following are representative:
2,2-bis-(3,5-dichlorophenyl)-propane; bis-(2-chlorophenyl)-methane;
bis(2,6-dibromophenyl)-methane; 1,1-bis-(4-iodophenyl)-ethane;
1,2-bis-(2,6-dichlorophenyl)-ethane;
1,1-bis-(2-chloro-4-iodophenyl)ethane;
1,1-bis-(2-chloro-4-methylphenyl)-ethane;
1,1-bis-(3,5-dichlorophenyl)-ethane;
2,2-bis-(3-phenyl-4-bromophenyl)-ethane;
2,6-bis-(4,6-dichloronaphthyl)-propane;
2,2-bis-(2,6-dichlorophenyl)-pentane;
2,2-bis-(3,5-dibromophenyl)-hexane;
bis-(4-chlorophenyl)-phenyl-methane;
bis-(3,5-dichlorophenyl)-cyclohexylmethane;
bis-(3-nitro-4-bromophenyl)-methane;
bis-(4-hydroxy-2,6-dichloro-3-methoxyphenyl)-methane; and
2,2-bis-(3,5-dichloro-4-hydroxyphenyl)-propane 2,2
bis-(3-bromo-4-hydroxyphenyl)-propane. Also included within the
above structural formula are: 1,3-dichlorobenzene,
1,4-dibromobenzene, 1,3-dichloro-4-hydroxybenzene, and biphenyls
such as 2,2'-dichlorobiphenyl, polybrominated 1,4-diphenoxybenzene,
2,4'-dibromobiphenyl, and 2,4'-dichlorobiphenyl as well as
decabromo diphenyl oxide, and the like.
[0056] Also useful are oligomeric and polymeric halogenated
aromatic compounds, such as a copolycarbonate of bisphenol A and
tetrabromobisphenol A and a carbonate precursor, e.g., phosgene.
Metal synergists, e.g., antimony oxide, may also be used with the
flame retardant. When present, halogen containing flame retardants
can be present in amounts of about 0.1 to about 10 percent by
weight, based on the total weight of the polycarbonate.
[0057] Inorganic flame retardants may also be used, for example
salts of C.sub.2-16 alkyl sulfonate salts such as potassium
perfluorobutane sulfonate (Rimar salt), potassium perfluoroctane
sulfonate, tetraethylammonium perfluorohexane sulfonate, and
potassium diphenylsulfone sulfonate, and the like; salts formed by
reacting for example an alkali metal or alkaline earth metal (for
example lithium, sodium, potassium, magnesium, calcium and barium
salts) and an inorganic acid complex salt, for example, an
oxo-anion, such as alkali metal and alkaline-earth metal salts of
carbonic acid, such as Na.sub.2CO.sub.3, K.sub.2CO.sub.3,
MgCO.sub.3, CaCO.sub.3, and BaCO.sub.3 or fluoro-anion complexes
such as Li.sub.3AlF.sub.6, BaSiF.sub.6, KBF.sub.4,
K.sub.3AlF.sub.6, KAlF.sub.4, K.sub.2SiF.sub.6, and/or
Na.sub.3AlF.sub.6 or the like. When present, inorganic flame
retardant salts can be present in amounts of 0.1 to 5 percent by
weight, based on the total weight of the polycarbonate.
[0058] While the polycarbonate composition is of a viscosity and
flow suitable for the application, it is contemplated that
conventional flow promoters and plasticizers may still be desired
for certain embodiments. Examples of suitable flow promoters and
plasticizers include the phosphate plasticizers such as cresyl
diphenyl phosphate, triphenyl phosphate, tricresyl phosphate,
isopropylated and triphenyl phosphate. Terepene phenol, saturated
alicyclic hydrocarbons, chlorinated biphenols, and mineral oil are
also suitable. When used, plasticizers are typically employed in an
amount of about 0.1 to about 10 wt % based on the weight of the
polycarbonate.
[0059] The polycarbonate composition also optionally includes an
anti-drip agent such as a fluoropolymer. The fluoropolymer may be a
fibril forming or non-fibril forming fluoropolymer. The
fluoropolymer generally used is a fibril forming polymer. In some
embodiments the fluoropolymer comprises polytetrafluoroethylene. In
some embodiments an encapsulated fluoropolymer may be employed,
i.e. a fluoropolymer encapsulated in a polymer. An encapsulated
fluoropolymer may be made by polymerizing the polymer in the
presence of the fluoropolymer. Alternatively, the fluoropolymer may
be pre-blended with a second polymer, such as for example, an
aromatic polycarbonate resin or a styrene-acrylonitrile resin to
form an agglomerated material for use as an anti-drip agent. Either
method may be used to produce an encapsulated fluoropolymer.
[0060] The anti-drip agent, when present, comprises 0.1 to 5 weight
percent, more specifically 0.5 to 3.0 weight percent and most
specifically 1.0 to 2.5 weight percent based on the total weight of
the polycarbonate.
[0061] The polycarbonate composition may further comprise a
colorant. Suitable dyes include, for example, organic dyes such as
coumarin 460 (blue), coumarin 6 (green), nile red or the like;
lanthanide complexes; hydrocarbon and substituted hydrocarbon dyes;
polycyclic aromatic hydrocarbons; scintillation dyes (preferably
oxazoles and oxadiazoles); aryl- or heteroaryl-substituted poly
(C.sub.2-8 olefins); carbocyanine dyes; phthalocyanine dyes and
pigments; oxazine dyes; carbostyryl dyes; porphyrin dyes; acridine
dyes; anthraquinone dyes; arylmethane dyes; azo dyes; diazonium
dyes; nitro dyes; quinone imine dyes; tetrazolium dyes; thiazole
dyes; perylene dyes, perinone dyes; bis-benzoxazolylthiophene
(BBOT); and xanthene dyes; fluorophores such as anti-stokes shift
dyes which absorb in the near infrared wavelength and emit in the
visible wavelength, or the like; luminescent dyes such as
5-amino-9-diethyliminobenzo(a)phenoxazonium perchlorate;
7-amino-4-methylcarbostyryl; 7-amino-4-methylcoumarin;
7-amino-4-trifluoromethylcoumarin;
3-(2'-benzimidazolyl)-7-N,N-diethylaminocoumarin;
3-(2'-benzothiazolyl)-7-diethylaminocoumarin;
2-(4-biphenylyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole;
2-(4-biphenylyl)-5-phenyl-1,3,4-oxadiazole;
2-(4-biphenyl)-6-phenylbenzoxazole-1,3;
2,5-Bis-(4-biphenylyl)-1,3,4-oxadiazole;
2,5-bis-(4-biphenylyl)-oxazole;
4,4'-bis-(2-butyloctyloxy)-p-quaterphenyl;
p-bis(o-methylstyryl)-benzene; 5,9-diaminobenzo(a)phenoxazonium
perchlorate;
4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran;
1,1'-diethyl-2,2'-carbocyanine iodide;
1,1'-diethyl-4,4'-carbocyanine iodide;
3,3'-diethyl-4,4',5,5'-dibenzothiatricarbocyanine iodide;
1,1'-diethyl-4,4'-dicarbocyanine iodide;
1,1'-diethyl-2,2'-dicarbocyanine iodide;
3,3'-diethyl-9,11-neopentylenethiatricarbocyanine iodide;
1,3'-diethyl-4,2'-quinolyloxacarbocyanine iodide;
1,3'-diethyl-4,2'-quinolylthiacarbocyanine iodide;
3-diethylamino-7-diethyliminophenoxazonium perchlorate;
7-diethylamino-4-methylcoumarin;
7-diethylamino-4-trifluoromethylcoumarin; 7-diethylaminocoumarin;
3,3'-diethyloxadicarbocyanine iodide; 3,3'-diethylthiacarbocyanine
iodide; 3,3'-diethylthiadicarbocyanine iodide;
3,3'-diethylthiatricarbocyanine iodide;
4,6-dimethyl-7-ethylaminocoumarin; 2,2'-dimethyl-p-quaterphenyl;
2,2-dimethyl-p-terphenyl;
7-dimethylamino-1-methyl-4-methoxy-8-azaquinolone-2;
7-dimethylamino-4-methylquinolone-2;
7-dimethylamino-4-trifluoromethylcoumarin;
2-(4-(4-dimethylaminophenyl)-1,3-butadienyl)-3-ethylbenzothiazolium
perchlorate;
2-(6-(p-dimethylaminophenyl)-2,4-neopentylene-1,3,5-hexatrienyl)-3-methyl-
benzothiazolium perchlorate;
2-(4-(p-dimethylaminophenyl)-1,3-butadienyl)-1,3,3-trimethyl-3H-indolium
perchlorate; 3,3'-dimethyloxatricarbocyanine iodide;
2,5-diphenylfuran; 2,5-diphenyloxazole; 4,4'-diphenylstilbene;
1-ethyl-4-(4-(p-dimethylaminophenyl)-1,3-butadienyl)-pyridinium
perchlorate;
1-ethyl-2-(4-(p-dimethylaminophenyl)-1,3-butadienyl)-pyridinium
perchlorate;
1-Ethyl-4-(4-(p-dimethylaminophenyl)-1,3-butadienyl)-quinolium
perchlorate; 3-ethylamino-7-ethylimino-2,8-dimethylphenoxazin-5-ium
perchlorate;
9-ethylamino-5-ethylamino-10-methyl-5H-benzo(a)phenoxazonium
perchlorate; 7-ethylamino-6-methyl-4-trifluoromethylcoumarin;
7-ethylamino-4-trifluoromethylcoumarin;
1,1',3,3,3',3'-hexamethyl-4,4',5,5'-dibenzo-2,2'-indotricarboccyanine
iodide; 1,1',3,3,3',3'-hexamethylindodicarbocyanine iodide;
1,1',3,3,3',3'-hexamethylindotricarbocyanine iodide;
2-methyl-5-t-butyl-p-quaterphenyl;
N-methyl-4-trifluoromethylpiperidino-<3,2-g>coumarin;
3-(2'-N-methylbenzimidazolyl)-7-N,N-diethylaminocoumarin;
2-(1-naphthyl)-5-phenyloxazole;
2,2'-p-phenylen-bis(5-phenyloxazole);
3,5,3'''',5''''-tetra-t-butyl-p-sexiphenyl;
3,5,3'''',5''''-tetra-t-butyl-p-quinquephenyl;
2,3,5,6-1H,4H-tetrahydro-9-acetylquinolizino-<9,9a,
1-gh>coumarin;
2,3,5,6-1H,4H-tetrahydro-9-carboethoxyquinolizino-<9,9a,
1-gh>coumarin;
2,3,5,6-1H,4H-tetrahydro-8-methylquinolizino-<9,9a,
1-gh>coumarin;
2,3,5,6-1H,4H-tetrahydro-9-(3-pyridyl)-quinolizino-<9,9a,
1-gh>coumarin;
2,3,5,6-1H,4H-tetrahydro-8-trifluoromethylquinolizino-<9,9a,
1-gh>coumarin; 2,3,5,6-1H,4H-tetrahydroquinolizino-<9,9a,
1-gh>coumarin; 3,3',2'',3'''-tetramethyl-p-quaterphenyl;
2,5,2'''',5'''-tetramethyl-p-quinquephenyl; P-terphenyl;
P-quaterphenyl; nile red; rhodamine 700; oxazine 750; rhodamine
800; IR 125; IR 144; IR 140; IR 132; IR 26; IR5;
diphenylhexatriene; diphenylbutadiene; tetraphenylbutadiene;
naphthalene; anthracene; 9,10-diphenylanthracene; pyrene; chrysene;
rubrene; coronene; phenanthrene or the like, or a combination
comprising at least one of the foregoing dyes.
[0062] Suitable colorants include, for example titanium dioxide,
anthraquinones, perylenes, perinones, indanthrones, quinacridones,
xanthenes, oxazines, oxazolines, thioxanthenes, indigoids,
thioindigoids, naphtalimides, cyanines, xanthenes, methines,
lactones, coumarins, bis-benzoxaxolylthiophenes (BBOT),
napthalenetetracarboxylic derivatives, monoazo and disazo pigments,
triarylmethanes, aminoketones, bis(styryl)biphenyl derivatives, and
the like, as well as combinations comprising at least one of the
foregoing colorants. Dyes are generally used in amounts of about
0.01 to about 5 wt %, based on the total weight of the
polycarbonate.
[0063] The polycarbonate film may also comprise an antistatic
agent. The term "antistatic agent" refers to monomeric, oligomeric,
or polymeric materials that can be processed into polymer resins
and/or sprayed onto materials or articles to improve conductive
properties and overall physical performance. Examples of monomeric
antistatic agents include glycerol monostearate, glycerol
distearate, glycerol tristearate, ethoxylated amines, primary,
secondary and tertiary amines, ethoxylated alcohols, alkyl
sulfates, alkylarylsulfates, alkylphosphates, alkylaminesulfates,
alkyl sulfonate salts such as sodium stearyl sulfonate, sodium
dodecylbenzenesulfonate or the like, quaternary ammonium salts,
quaternary ammonium resins, imidazoline derivatives, sorbitan
esters, ethanolamides, betaines, or the like, or combinations
comprising at least one of the foregoing monomeric antistatic
agents.
[0064] Exemplary polymeric antistatic agents include certain
polyesteramides polyether-polyamide (polyetheramide) block
copolymers, polyetheresteramide block copolymers, polyetheresters,
or polyurethanes, each containing polyalkylene glycol moieties
polyalkylene oxide units such as polyethylene glycol, polypropylene
glycol, polytetramethylene glycol, and the like. Such polymeric
antistatic agents are commercially available, for example
Pelestat.RTM. 6321 (Sanyo) or Pebax.RTM. MH1657 (Atofina),
Irgastat.RTM. P18 and P22 (Ciba-Geigy). Other polymeric materials
that may be used as antistatic agents are inherently conducting
polymers such as polyaniline (commercially available as
PANIPOL.RTM.EB from Panipol), polypyrrole and polythiophene
(commercially available from Bayer), which retain some of their
intrinsic conductivity after melt processing at elevated
temperatures. In one embodiment, carbon fibers, carbon nanofibers,
carbon nanotubes, carbon black, or any combination of the foregoing
may be used in a polymeric resin containing chemical antistatic
agents to render the composition electrostatically dissipative.
Antistatic agents can be used in amounts of 0.0001 to 5 percent by
weight, based on the total weight of the polycarbonate.
[0065] The polycarbonate compositions for use in preparing
polycarbonate films may be manufactured by methods generally
available in the art. For example, in an embodiment, a powdered
polycarbonate resin and any other components are first blended in a
HENSCHEL-Mixer.RTM. high speed mixer. Other low shear processes
including but not limited to hand mixing may also accomplish this
blending. The blend is then fed into the throat of a twin-screw
extruder via a hopper. Alternatively, one or more of the components
may be incorporated into the composition by feeding directly into
the extruder at the throat and/or downstream through a sidestuffer.
Such additives may also be compounded into a masterbatch with a
desired polymeric resin and fed into the extruder. The additives
may be added to the polycarbonate base material to make a
concentrate, before this is added to the final product. The
extruder is generally operated at a temperature higher than that
necessary to cause the composition to flow, typically about 260 to
about 350.degree. C. The extrudate is immediately quenched in a
water batch and pelletized. The pellets, prepared by cutting the
extrudate, may be about one-fourth inch long or less as desired.
Such pellets may be used for subsequent extrusion, casting,
molding, shaping, or forming of a polycarbonate film. The
polycarbonate film may have a thickness of about 25 to about 1,270
micrometers, specifically about 127 to about 760 micrometers.
[0066] The composite film further comprises a protective layer. In
an advantageous feature, the protective layer comprises a film
comprising an adhesion-modified polyolefin that is effective to
provide the desired level of adhesion and adhesion stability during
use. The adhesion-modified polyolefin may be used alone or in
combination (e.g., as a blend) with another polyolefin to form the
film. The protective layer may further comprise an additional film,
for example an unmodified polyolefin or other type of protective
film, in combination with the adhesion-modified polyolefin
film.
[0067] The adhesion-modified polyolefin may be obtained by
copolymerization of an adhesion-improving comonomer with a
C.sub.2-18 olefin, for example ethylene, propylene, or a
combination of ethylene and propylene. A specific monomer is
ethylene. As used herein an "adhesion improving monomer" is a
monomer that is copolymerizable with a C.sub.2-18 olefin and which
is useful for adjusting the adhesion of the protective layer to the
substrate to an appropriate level and increase the stability of the
adhesion during use. Suitable comonomers include, for example,
alkenyl esters such as vinyl esters of C.sub.1-C.sub.36 linear or
branched aliphatic carboxylic acids, cyclic aliphatic acids, aryl
containing acids, or combinations of one or more of the foregoing
types of acids. Examples of suitable vinyl esters include but are
not limited to vinyl acetate, vinyl propionate, vinyl butyrate,
vinyl pivalate, vinyl 2-ethylhexanoate, vinyl versalate, and the
like. Combinations comprising one or more of these may be used. The
vinyl ester monomer may be present in the adhesion modified
polyolefin copolymer an amount of about 2 to about 20 wt %,
specifically about 7 to about 10 wt % of the monomer charge.
[0068] Additional copolymerizable monomers may be used to form the
adhesion-modified polyolefin. Such monomers may include vinyl
ethers, vinyl halides, vinyl alcohols, ethylenically unsaturated
carboxylic acids such as acrylic acids and methacrylic acids,
acrylamide, acrylonitrile, cyclic olefins, for example
cyclohexenes, norbornenes, cyclopentadiene, and cyclopentadiene
derivatives, dienes such as butadiene and isoprene, vinyl aromatic
monomers such as styrene, alpha-methylstyrene, 3- and
4-acetoxystyrenes, 4-alkoxystyrenes (including 4-methoxystyrene and
4-t-butoxystyrene), and the like, or combination comprising at
least one of the foregoing comonomers. Additional monomer may be
present in the adhesion modified polyolefin copolymer an amount of
about 1 to about 50 wt %, specifically about 2 to about 20 wt % of
the monomer charge.
[0069] Any suitable method known for the formation of polyolefin
copolymers may be used to provide the adhesion-modified
polyolefins. Specifically suitable polymerization methods for
preparing adhesion modified polyolefins include radical
polymerization methods for the preparation of random copolymers of
the adhesion modified polyolefin.
[0070] As stated above, the adhesion-modified polyolefins may be
used in combination with unmodified polyolefins, for example in the
form of a blend or laminated to a film of an unmodified polyolefin.
Suitable unmodified polyolefins include homopolymers and copolymers
of C.sub.2-18 olefins. In an embodiment, the unmodified polyolefin
may be a polyethylene, polypropylene, or ethylene-propylene
copolymer. The unmodified polyolefins may be predominantly branched
or linear, having a low degree of crystallinity and low density.
Low density polyolefins, such as low density polyethylene, prepared
using standard olefin polymerization techniques, such as radical
polymerization or using Ziegler-Natta olefin polymerization
catalysts, are suitable. Also suitable are polyolefins having a
controlled branching structure, which conveys a greater dimensional
stability and greater shear resistance in the polymer, and which
may be processed or extruded to form thinner layers without loss of
film integrity. Suitable polyolefins of this type include linear
low density polyolefins, prepared using a single-site activation
metallocene catalysts derived from transition metals such as
zirconium, titanium, hafnium, and the like. A specific example of a
suitable polymer is a linear low density polyethylene (LLDPE). In a
specific embodiment, polyethylene, more specifically polyethylene
having a melt volume rate (MVR) according to ASTM D1238-04 of about
0.1 to about 8 cc/10 min, and a density of about 0.91 to about 0.94
g/cm.sup.3 may be used.
[0071] When a combination of a polyolefin and an adhesion-modified
polyolefin is used to form the protective film, the adhesion
modified polyolefin can be present in an amount from about 40 to
about 90 wt %, specifically about 45 to about 85 wt % based on the
amount of unmodified polyolefin. Conversely, the amount of
unmodified polyolefin can be from about 10 to about 60 wt %,
specifically about 15 to about 55 wt % based on the weight of the
adhesion modified polyolefin.
[0072] Other adhesion promoting additives, for example tackifiers,
may be added to the adhesion-modified polyolefin protective film.
The addition of a tackifier increases the adhesive force between
layers. Tackifiers generally have a relatively low molecular mass,
typically about 200 to about 2,000 g/mol, with a wide molecular
mass distribution and a glass transition temperature (T.sub.g)
above that of an elastomer. The softening point of tackifiers is
typically about 50 to about 150.degree. C.
[0073] Suitable tackifiers may include terpene oligomers, cumarone
indene resins, aliphatic petrochemical resins, and modified phenol
resins. Terpene tackifiers are prepared by polymerization,
particularly cationic polymerization of naturally occurring
terpenes such as the pinenes, limonenes and the like. Aliphatic
petrochemical resins are generally obtained by oligomerization of
petroleum fractions, specifically hydrogenated fractions. Examples
include hydrogenated hydrocarbon resins based on polymerizable
C.sub.9 olefinic hydrocarbons (obtained from petroleum distillation
fractions), copolymerized with a second monomer such as indene,
alpha-methylstyrene, or vinyl toluene. Hydrogenated hydrocarbon
resin based on polymerized cyclopentadiene that is subsequently
hydrogenated may also be suitable. The tackifier, when present in
the protective film, is used in an amount of about 0.5 to about 20
wt %, specifically about 2 to about 20 wt %, relative to the weight
percentage of the adhesion modified polyolefin or the combination
of adhesion modified polyolefin and unmodified polyolefin.
Likewise, the adhesion modified polyolefin or combination of
adhesion modified polyolefin and unmodified polyolefin are used in
an amount of about 80 to about 99.5 wt % relative to the
tackifier.
[0074] In an embodiment, the protective layer comprises a film
comprising the adhesion-modified polyolefin, optionally together
with a tackifier. The film may further comprise an unmodified
polyolefin (with or without a tackifier). The thickness of this
film may be about 5 to about 40 micrometers, specifically about 10
to about 30 micrometers.
[0075] In another embodiment, one of the foregoing films is used
together with a second film comprising an unmodified polyolefin,
with or without a tackifier. Additional film layers may also be
present, provided that at least one face of the adhesion-modified
film is exposed. For example, one or more layers may be disposed
between the first and second film. The thickness of this second
film and any additional films may be about 20 to about 150
micrometers. Multi-layered protective layers may be produced by
coextrusion of the films using a flat or annular die. The total
film thickness for a multi-layered protective layer may be about 25
to about 190 micrometers, specifically about 30 to about 150
micrometers. For example, suitable adhesion-modified polyolefin
protective layers having a thickness of about 50 micrometers, and
having the desired adhesive properties, include polyethylene (PE)
masking GHX 173 R and GHX 174 A, both available from Bischof and
Klein GmbH of Lengerich, Germany.
[0076] The composite film further comprises a coating layer, which
is disposed between the protective layer and the polycarbonate
film. The coating layer is derived from a coating composition
comprising a crosslinkable compound, an initiator, and a binder,
which is cured to form the crosslinked coating layer using light,
heat, pressure, or a combination comprising at least one of the
foregoing cure mechanisms.
[0077] The crosslinking compounds comprising the coating layer may
crosslink using a variety of different reaction mechanisms,
including free radical, acid catalyzed, or thermally initiated, and
thus may have a variety of reactive groups for accomplishing the
crosslinking reaction. Crosslinking reactive groups that may be
present include epoxides, methylols, anhydrides, esters,
cyclobutenes, (meth)acrylates, and the like, or a combination
comprising one or more of the foregoing reactive groups.
Specifically, radically initiated crosslinkable compounds
comprising ethylenically unsaturated groups, such as polyfunctional
alkenyl aromatic compounds, acryloyl-containing compounds, and the
like, which have high reactivity and minimal shrinkage upon cure,
are suitable for use herein.
[0078] Suitable polyfunctional alkenyl aromatic compounds may have
the structure of formula (17): ##STR16## wherein each R.sup.16 is
independently hydrogen, C.sub.1-C.sub.12 alkyl, C.sub.2-C.sub.12
alkenyl, C.sub.2-C.sub.12 alkynyl, C.sub.6-C.sub.18 aryl, or the
like; each R.sup.17 is independently halogen, C.sub.1-C.sub.12
alkyl, C.sub.1-C.sub.12 alkoxyl, C.sub.6-C.sub.18 aryl, or the
like; p is 2 to 4; and q is 0 to 4. Specific suitable
polyfunctional alkenyl aromatic compounds include
1,2-divinylbenzene, 1,3-divinylbenzene, 1,4-divinylbenzene,
trivinylbenzenes, 1,3-diisopropenylbenzene,
1,4-diisopropenylbenzene, and the like; and combinations comprising
at least one of the foregoing compounds. In the foregoing compounds
for which no substituent position is specified, the substituents
may occupy any free position on the aromatic ring.
[0079] A suitable acryloyl-containing compound is a polyfunctional
(meth)acryloyl compound comprising at least two (meth)acryloyl
moieties having the structure of formula (18): ##STR17## wherein
R.sup.18 and R.sup.19 are each independently hydrogen,
C.sub.1-C.sub.12 alkyl, or the like; and wherein R.sup.18 and
R.sup.19 may be disposed either cis or trans about the
carbon-carbon double bond. Preferably, R.sup.18 and R.sup.19 are
each independently hydrogen or methyl. Specifically, the
polyfunctional (meth)acryloyl compound comprises at least two
(meth)acryloyl moieties having the structure of formula (19):
##STR18## wherein R.sup.20-R.sup.22 are each independently
hydrogen, C.sub.1-C.sub.12 alkyl, C.sub.2-C.sub.12 alkenyl,
C.sub.6-C.sub.18 aryl, C.sub.7-C.sub.18 alkyl-substituted aryl,
C.sub.7-C.sub.18 aryl-substituted alkyl, C.sub.2-C.sub.12
alkoxycarbonyl, C.sub.7-C.sub.18 aryloxycarbonyl, C.sub.8-C.sub.18
alkyl-substituted aryloxycarbonyl, C.sub.8-C.sub.18
aryl-substituted alkoxycarbonyl, nitrile, formyl, carboxylate,
imidate, thiocarboxylate, or the like. Preferably,
R.sup.20-R.sup.22 are each independently hydrogen or methyl.
[0080] Suitable polyfunctional (meth)acryloyl compounds include,
for example, unsaturated polyester resins that are the
polycondensation reaction product of one or more dihydric alcohols
and one or more ethylenically unsaturated polycarboxylic acids. By
polycarboxylic acid is meant polycarboxylic or dicarboxylic acids
or anhydrides, polycarboxylic or dicarboxylic acid halides, and
polycarboxylic or dicarboxylic esters. For example, suitable
unsaturated polycarboxylic acids, and corresponding anhydrides and
acid halides that contain polymerizable carbon-to-carbon double
bonds, may include maleic anhydride, maleic acid, and fumaric acid.
A minor proportion of the unsaturated acid, up to about 40 mole
percent, may be replaced by dicarboxylic or polycarboxylic acid
that does not contain a polymerizable carbon-to-carbon bond.
Examples thereof include the acids (and corresponding anhydrides
and acid halides): phthalic, isophthalic, terephthalic, succinic,
adipic, sebasic, methylsuccinic, and the like. Dihydric alcohols
that are useful in preparing the polyesters include, for example,
1,2-propanediol (hereinafter referred to as propylene glycol),
dipropylene glycol, diethylene glycol, 1,3-butanediol, ethylene
glycol, glycerol, and the like. Examples of suitable unsaturated
polyesters are the polycondensation products of propylene glycol
and maleic and/or fumaric acids; 1,3-butanediol and maleic and/or
fumaric acids; combinations of ethylene and propylene glycols
(approximately 50 mole percent or less of ethylene glycol) and
maleic and/or fumaric acids; propylene glycol, maleic and/or
fumaric acids and dicyclopentadiene reacted with water; and the
like; and combinations comprising at least one of the foregoing
polyfunctional (meth)acryloyl monomers. In addition to the above
described polyesters, dicyclopentadiene-modified unsaturated
polyester resins such as those described in U.S. Pat. No. 3,883,612
to Pratt et al. may be used. The molecular weight of the
polymerizable unsaturated polyester may vary over a considerable
range, but ordinarily useful polyesters have a number average
molecular weight of about 300 to about 5,000, and more specifically
about 500 to about 5,000.
[0081] Suitable crosslinkable compounds may be difunctional,
trifunctional, tetrafunctional, or pentafunctional (meth)acryloyl
compounds. For example, difunctional compounds may be produced by
condensation of an acrylic or methacrylic acid with a diol under
esterification conditions, or condensed with a di-epoxide, such as
bisphenol-A diglycidyl ether, butanediol diglycidyl ether, or
neopenylene glycol dimethacrylate. Specific examples of
difunctional compounds prepared this way include 1,4-butanediol
diglycidylether di(meth)acrylate, bisphenol A diglycidylether
dimethacrylate, and neopentylglycol diglycidylether
di(meth)acrylate, and the like. Also included as polyfunctional
(meth)acryloyl monomers are the condensation of reactive acrylate
or methacrylate compounds with alcohols or amines to produce the
resulting polyfunctional (meth)acrylates or polyfunctional
(meth)acrylamides, respectively. Examples of these include
N,N-bis(2-hydroxyethyl)(meth)acrylamide,
methylenebis((meth)acrylamide),
1,6-hexamethylenebis((meth)acrylamide), diethylenetriamine
tris((meth)acrylamide), bis(gamma-((meth)acrylamide)propoxy)ethane,
beta-((meth)acrylamide) ethylacrylate, ethylene glycol
di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene
glycol di(meth)acrylate, glycerol di(meth)acrylate, glycerol
tri(meth)acrylate, 1,3-propylene glycol di(meth)acrylate,
dipropyleneglycol di(meth)acrylate, 1,4-butanediol
di(meth)acrylate, 1,2,4-butanetriol tri(meth)acrylate,
1,6-hexanedioldi(meth)acrylate, 1,4-cyclohexanediol
di(meth)acrylate, 1,4-benzenediol di(meth)acrylate,
pentaerythritoltetra(meth)acrylate, 1,5-pentanediol
di(meth)acrylate, 1,8-octanediol diacrylate, 1,9-nonanediol
di(meth)acrylate, 1,10-decanediol di(meth)acrylate,
1,11-undecanediol di(meth)acrylate, 1,12-dodecanediol
di(meth)acrylate, pentaerythritol tri(meth)acrylate,
pentaerythritol tetra(meth)acrylate, dipentaerythritol
tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate,
diethylene glycol di(meth)acrylate, triethylene glycol
di(meth)acrylate, trimethylolpropane di(meth)acrylate,
trimethylolpropane tri(meth)acrylate),
1,3,5-triacryloylhexahydro-1,3,5-triazine,
2,2-bis(4-(2-(meth)acryloxyethoxy)phenyl)propane,
2,2-bis(4-(2-(meth)acryloxyethoxy)-3,5-dibromophenyl)propane,
2,2-bis((4-(meth)acryloxy)phenyl)propane,
2,2-bis((4-(meth)acryloxy)-3,5-dibromophenyl)propane, and the like,
and combinations comprising at least one of the foregoing
polyfunctional (meth)acryloyl monomers. It will be understood that
the suffix (meth)acryl- denotes either acryl- or methacryl-. In an
embodiment, one or more acrylate crosslinkable compounds having a
high reactivity are used.
[0082] The curable, ethylenically unsaturated, crosslinkable
coating compositions described above further comprise a
polymerization initiator to promote polymerization of the curable
components. Suitable polymerization initiators include
photoinitiators that promote polymerization of the components upon
exposure to ultraviolet radiation. Particularly suitable
photoinitiators include phosphine oxide photoinitiators. Examples
of such photoinitiators include the IRGACURE.RTM. and DAROCUR.RTM.
series of phosphine oxide photoinitiators available from Ciba
Specialty Chemicals; the LUCIRIN.RTM. series from BASF Corp.; and
the ESACURE.RTM. series of photoinitiators available from Lamberti.
Other useful photoinitiators include ketone-based photoinitiators,
such as hydroxyalkyl phenyl ketones and alkoxyalkyl phenyl ketones,
and thioalkylphenyl morpholinoalkyl ketones. Also suitable are
benzoin ether photoinitiators. Combinations of the foregoing
photoinitiators may be used. A specific suitable initiator is
diethoxy acetophenone.
[0083] The polymerization initiator may include peroxy-based
initiators that promote polymerization under thermal activation.
Examples of useful peroxy initiators include, for example, benzoyl
peroxide, dicumyl peroxide, methyl ethyl ketone peroxide, lauryl
peroxide, cyclohexanone peroxide, t-butyl hydroperoxide, t-butyl
benzene hydroperoxide, t-butyl peroctoate,
2,5-dimethylhexane-2,5-dihydroperoxide,
2,5-dimethyl-2,5-di(t-butylperoxy)-hex-3-yne, di-t-butylperoxide,
t-butylcumyl peroxide,
alpha,alpha'-bis(t-butylperoxy-m-isopropyl)benzene,
2,5-dimethyl-2,5-di(t-butylperoxy)hexane, dicumylperoxide,
di(t-butylperoxy) isophthalate, t-butylperoxybenzoate,
2,2-bis(t-butylperoxy)butane, 2,2-bis(t-butylperoxy)octane,
2,5-dimethyl-2,5-di(benzoylperoxy)hexane,
di(trimethylsilyl)peroxide, trimethylsilylphenyltriphenylsilyl
peroxide, and the like, and combination comprising at least one of
the foregoing.
[0084] The polymerization initiator may be used in an amount
effective to promote curing of the curable composition. For
example, the polymerization initiator may be used in an amount of
about 0.01 to about 10 wt %, specifically about 0.1 to about 5 wt
%, based on the total weight of the crosslinkable compound,
initiator, and binder.
[0085] The coating composition also comprises a binder for use in
controlling the flow and distribution properties of the coating
composition, and which may act as a viscosity modifier. Suitable
binder materials include modified and unmodified polysaccharide
based materials such as celluloses, starch, dextrins,
lignocelluloses, and the like, and may be modified to adjust the
viscosity, polarity, solubility, and other properties by
esterification of the hydroxyl groups on the base material using a
reactive C.sub.2-30 carboxylic acid derivative, to provide the
esterified binder. Particularly useful carboxylic acids include
those having fewer than 8 carbons, suitable examples of which
include acetic acid, propionic acid, butyric acid, isobutyric acid,
a combination comprising at least one of the foregoing carboxylic
acids, and derivatives thereof. In an exemplary embodiment, useful
ester-modified binder materials for the coating composition include
cellulose acetate and cellulose acetate butyrate. The binder is
present in the coating composition in an amount of about 1 to about
25 wt %, specifically about 2 to about 15 wt % of the total weight
of the crosslinkable compound, initiator, and binder.
[0086] The coating composition comprises a combination comprising
two or more polyfunctional crosslinkable compounds. In an
embodiment, a useful coating composition comprises a combination of
difunctional, trifunctional, and tetrafunctional and/or
pentafunctional (meth)acrylate crosslinkable compounds, in which
the difunctional crosslinkable compound may be present in an amount
of about 20 to about 60 wt %, specifically about 25 to about 50 wt
%; the trifunctional crosslinkable compound may be present in an
amount of about 20 to about 60 wt %, specifically about 25 to about
50 wt %; the tetrafunctional and/or pentafunctional crosslinkable
compounds may be present in a total amount of about 12 to about 30
wt %, specifically about 15 to about 25 wt %; where the amounts of
each of these is based on the combined weights of the difunctional,
trifunctional, and tetrafunctional and/or pentafunctional
(meth)acrylate crosslinkable compounds, the initiator, and the
binder. An example of such a coating composition is described in
U.S. Pat. No. 5,455,105 to Coyle et al.
[0087] The composite film is prepared by layering a polycarbonate
film with a protective layer, and providing a suitable adhesive
bond between these by disposing therebetween the coating
composition, and curing the coating composition to form a coating
layer. The layered film may be prepared by lamination of the
polycarbonate and protective films subsequent to the application of
a layer of the coating composition to one or more faces of the
films to be adhered together. Application of the coating
composition to form a coating layer may be accomplished by spray
coating, layering, wiping, dipping, or other mechanical means of
creating a thin, uniform film of the coating composition to the
polycarbonate and/or protective layer surface. In a specific
embodiment, the coating composition is applied to the polycarbonate
film and initiated to form crosslinks. In another embodiment, the
coating composition is applied to a carrier layer and is partially
or fully cured, and is then applied to the polycarbonate film. The
polycarbonate film, coating layer, and protective film are then
layered together to form an uncured composite film. In an
embodiment, the polycarbonate film, coating layer, and protective
film are laminated together with a pressure roller. Heat and/or
light is applied to further cure the coating composition. The
resulting composite film, having a protective layer, polycarbonate
layer and coating layer disposed between, is collected and spooled.
The coating layer has a thickness of about 1 to about 130
micrometers, specifically about 1.5 to about 20 micrometers, and
still more specifically about 2 to about 5 micrometers.
[0088] An additional, second protective film having a lower degree
of adhesion may also be applied to the polycarbonate layer, on the
surface opposite the surface having the coating layer and
protective layer, where the applying may be performed
simultaneously with the formation of the composite film. This
second protective film is useful to protect the non-masked face of
the polycarbonate film during storage, transport, and handling, and
is removed prior to further processing of the composite film, such
as during the application of inks or other imaging chemicals at the
customer. The composite film may be shaped by cutting, drilling,
folding, layering, and other such shaping and forming operations,
to create a shape and size suitable for storage, transportation,
handling, and further processing.
[0089] An exemplary embodiment of the composite film is shown in
FIG. 1. FIG. 1 depicts a composite film 100 having a protective
layer 110 comprising the adhesion modified polyolefin 120, a
coating layer 130, and a polycarbonate layer 140. The coating layer
130 is disposed between the protective layer 110 and polycarbonate
layer 140. As used herein, "disposed between" means in at least
partial contact with. A second protective layer 150 may be adhered
to the face of the polycarbonate layer opposite the coating layer.
This second protective layer 150 is removed by the customer prior
to manufacturing steps to expose a surface where additional layers
or coatings of inks, adhesives, protective coatings, and the like
are applied. The second protective layer is not subject to
manufacturing processes involving heat or light which can affect
the adhesion of the layers.
[0090] A second exemplary embodiment of the composite film is shown
in FIG. 2. FIG. 2 depicts a composite film 160 having a protective
layer 170 comprising a layer comprising the adhesion modified
polyolefin 120, an outer layer of the protective layer 180
comprising an unmodified polyolefin, a coating layer 130, and a
polycarbonate layer 140. The coating layer 130 is disposed between
the protective layer 170 and polycarbonate layer 140. A second
protective film 150 may be applied to a face of the polycarbonate
layer opposite the coating layer, and is removed by the customer
prior to manufacturing processes to expose a surface where
additional layers or coatings of inks, adhesives, protective
coatings, and the like, are applied.
[0091] After processing in a manufacturing operation, the
protective layer (as seen above, 100 in FIG. 1, and 160 in FIG. 2)
is removable in an end use application step. It is generally
desired that the protective layer remain adhered to the coating
layer and polycarbonate layer for the duration of the processing,
until such time as processing is completed and the protective layer
may be removed. Excessive adhesion between the protective layer and
the polycarbonate film is undesirable, as it may lead to surface
finish marring, deposits of coating layer remaining, tearing,
stretching, or other defects. Conversely, inadequate adhesion
between the protective layer and the polycarbonate film can cause
premature delamination during processing after exposure to
mechanical stresses, heat, cold, radiation, moisture, solvent, or
other stresses, with similar effect. Either of excess adhesion or
inadequate adhesion may manifest as a result of treatment of the
composite film under conditions of heat and radiation. For example,
the film may be exposed to one or more thermal treatments of about
65 to 93.degree. C. for about 4 to about 240 minutes, UV light
exposure of 500 millijoules per square centimeter (mJ/cm.sup.2) at
a wavelength of about 290 to about 405 nm, or a combination of
these. The number of such treatments of each of these conditions
can be as many as 10, or possibly more depending on the
application. The cumulative effect of exposure to these conditions
can effect chemical or physical changes that can in turn affect
adhesion properties of the protective layer and/or the adjacent
coating layer.
[0092] It has been unexpectedly found that adhering the protective
layer to a polycarbonate layer using a coating layer disposed
therebetween provides a suitable level of adhesion when the
protective layer comprises an adhesion modified polyolefin as
described above. Still more surprisingly, the adhesion between the
protective layer and the coating layer remains suitable for use
during and after exposure to conditions, such as heat, UV
radiation, or a combination of heat and UV radiation, which are
known to affect adhesion between layers. Adhesion outside of a
suitable set of values has been found after exposure of comparative
composite films to heat and/or UV radiation, where the comparative
composite films comprise polycarbonate films and protective films
adhered together without use of both a coating layer and a
protective layer comprising an adhesion-modified polyolefin.
[0093] In an embodiment, the composite film has an adhesion between
the protective layer and the polycarbonate layer of about 1.0 to
about 40 centi-Newtons per centimeter (cN/cm), both before and
after treating thermally at greater than or equal to about
90.degree. C. for greater than or equal to about 4 minutes, both
before and after treating photolytically by exposing the composite
film UV radiation at a wavelength of about 290 to about 405 nm at
an exposure dose of greater than or equal to about 500 mJ/cm.sup.2,
or both before and after treating using a combination of these, and
as measured using a 180 degree peel pull test of a 2.54 cm wide
strip at a pull rate of 25.4 cm/min. In a specific embodiment, the
composite film has an adhesion between the protective layer and the
polycarbonate layer of about 1 to about 20 centi-Newtons per
centimeter (cN/cm), specifically about 1.5 to about 15 cN/cm, and
more specifically about 2 to about 10 cN/cm, both before and after
treating thermally at greater than or equal to about 90.degree. C.
for greater than or equal to about 4 minutes, both before and after
treating photolytically by exposing the composite film UV radiation
at a wavelength of about 290 to about 405 nm at an exposure dose of
greater than or equal to about 500 mJ/cm.sup.2, or both before and
after treating using a combination of these, and as measured using
a 180 degree peel pull test of a 2.54 cm wide strip at a pull rate
of 25.4 cm/min. These values represent useful measures of adhesion
for mask processing and manufacturing purposes.
[0094] The composite film has an acceptably flat edge when laid out
upon a flat surface. Edge flatness may be compromised during
processing of the composite film due to exacerbation of differences
in physical properties of adjacent layers by exposure to processing
conditions. Changes in properties such as solvent swellability,
moisture absorbance, coefficients of thermal expansion, and/or
dimensional changes of the layers during processing may affect the
flatness of the masked polymer film. Film flatness, particularly at
the edges where poor flatness manifests as edge curl, is highly
desirable, so as to avoid difficulties in manufacturing and
processing step, and to allow for a smooth application to a
surface. Excessive edge curl may result in decreased process yield,
defective product, longer cycle times, increased down time for
processing equipment, and higher maintenance costs.
[0095] It is believed that the use of a coating composition having
a low degree of dimensional change, along the x, y, and z axes,
upon cure to form a coating layer minimizes the degree of curl at
the edges of the composite film. A minimum amount of dimensional
change upon curing may be less than about 5%, specifically less
than about 3%, more specifically less than about 2% along the axis
corresponding to the processing flow direction for the film. In an
embodiment, the degree of curl at the edge of a sample of the
composite film comprising a 250 micrometer thick polycarbonate film
is less than or equal to about 3.0 cm, specifically less than or
equal to about 2.8 cm, and more specifically less than or equal to
about 2.5 cm, both before and after treating thermally at greater
than or equal to about 90.degree. C. for greater than or equal to
about 4 minutes, both before and after treating photolytically by
exposing the composite film UV radiation at a wavelength of about
290 to about 405 nm at an exposure dose of greater than or equal to
about 500 mJ/cm.sup.2, or both before and after treating using a
combination of these. Similarly, the degree of curl at the edge of
a sample of the composite film comprising a 38 micrometer thick
polycarbonate film is less than or equal to about 1 cm,
specifically less than or equal to about 0.9 cm, and more
specifically less than or equal to about 0.75 cm both before and
after treating thermally at greater than or equal to about
90.degree. C. for greater than or equal to about 4 minutes, both
before and after treating photolytically by exposing the composite
film UV radiation at a wavelength of about 290 to about 405 nm at
an exposure dose of greater than or equal to about 500 mJ/cm.sup.2,
or both before and after treating using a combination of these.
[0096] The composite films as described above are specifically
useful in the printing and digital imaging industries. The
composite films are resistant to changes in the adhesive properties
between layers as a result of mechanical stresses by processing as
described above, or exposure to heat, UV radiation, moisture, or
chemicals in the form of inks, dyes, toners, paints, and other
imaging chemicals, as well as sources of light and heat for the
purpose of drying and curing the inks and other crosslinkable
applied materials.
[0097] In a representative set of processing conditions for
manufacturing a printed article, a sheet of the composite film
having an exposed face of the polycarbonate substrate is coated on
the exposed face of the polycarbonate substrate with a solvent ink
and oven cured for less than or equal to about 4 hours at about
65.degree. C. A first UV curable ink is applied to the cured
solvent ink surface, and the ink is crosslinked with UV radiation a
wavelength of about 290 to about 405 mm at an exposure dose about
500 mJ/cm.sup.2. A second UV curable ink may be applied over the
first, and the UV crosslinking process repeated, with as many as 10
such application/crosslink cycles performed. A layer of an adhesive
is applied to the surface having the crosslinked ink layers, and
the resulting film is dried in an oven at about 93.degree. C. for
about 5 minutes. A release layer is applied to the dried coating
layer, and the resulting article is cut to the desired size and
shape for use in a commercial application. Use of the article by a
secondary customer comprises removing the release layer to expose
the adhesive, applying the adhesive side of the article to a
substrate such as a glass window or painted surface, and removing
the protective layer to expose the coating layer and polycarbonate
surface.
[0098] Articles that may be prepared using the composite films
include transparent printed sheets, rolls, and designs for
application to solid surfaces such as opaque, transparent or
translucent materials such as glass windows for commercial and
residential use, automotive windshield glass, automotive dash
boards, flex membrane and rigid surfaces, displays for appliances,
labeling for identification of controls for mechanical and
electrical operated machines, equipment, and the like.
[0099] The above properties are further illustrated by the
following examples.
[0100] Peel strength was determined according to the following
method. Samples of the composite film were cut into one-inch wide
stripes and tested for peel resistance of the adhesive bond using a
180-degree peel test with a crosshead separation speed of 25.4 cm
per minute using an EJC Materials Tester from the Thwing-Albert
Instrument Company. The sample is first allowed to cool 10 minutes
after removal from the production line. Using the strip scribe
unit, three 18 cm long samples are cut to 2.5 cm width along the
machine direction. The second protective layer, if present, is
removed. Each strip is peeled back approximately 2.5 cm, the peeled
section doubled over by folding, and the folded sections clamped in
the instrument. The material is pulled apart at a rate of 25.4 cm
per minute, at an angle of 180.degree.. Three measurements are
taken at different places on each sample. The mean peel adhesion is
recorded in ounces of force (oz.) per 1-inch (2.54 cm) strip width.
The peel strength (P) was then calculated as follows: P=[peeling
load (ounces)]/[width of specimen (inches)], and converted to
metric units (centi-Newtons per centimeter, cN/cm) by multiplying
the force in ounce-inches by 10.95 cN/cm per 1 ounce/inch.
[0101] The degree of edge curl was determined using the following
method. Edge curl (wave appearance) is determined on trimmed film
products masked on both sides with protective layers. The film
specimen is initially cut in half along the machine direction,
wherein a 122 cm wide sample is cut into two 61 cm pieces; a 91 cm
wide sample is cut into two 45 cm pieces, or a 152 cm wide sample
is cut into two 76 cm pieces. The samples are laid out on flat
surface, with masking side up, and any trapped air pockets are
smoothed out from under the samples as much so as possible. With
steel ruler, the distance the material edges bow from the flat
surface is measured, at the maximum part of the wave. The sample is
checked on both the left and right edges on all tests. If the
sample is masked on two sides, the second protective layer (having
no coating layer) is removed and the procedure is repeated. The
highest measured edge curl is recorded.
[0102] The coating composition used in the preparation of examples
of the composite film was prepared by combining the following
components in the ratios shown in Table 1. TABLE-US-00001 TABLE 1
Acronym Component CAS Number Wt % HDODA Hexanediol Diacrylate
13048-33-4 40.00 TMPTA Trimethylolpropane Triacrylate 15625-89-5
40.00 DPEPA Dipentaerythritol Pentaacrylate 60506-81-2 11.30 DEAP
2,2-Diethoxy Acetophenone 6175-45-7 2.1 CAB Cellulose Acetate
Butyrate 9004-36-8 6.6 TOTAL 100
[0103] Examples 1-4. Laminates were prepared using bisphenol-A
polycarbonate films of 250 micrometers (10 mil) and 380 micrometers
(15 mil) thickness with Tru Cling.RTM. clear polyethylene masking
(Tredegar Corp.) applied to one side. The other, exposed face of
the polycarbonate film was coated with the coating composition
described in Table 1, and protected with either an applied film of
GHX 173 R PE film (Example 1: 250 micrometer polycarbonate film;
Example 3: 380 micrometer polycarbonate film) or GHX 174 A PE film
(Example 2: 250 micrometer polycarbonate film; Example 4: 380
micrometer polycarbonate film), each of 50 micrometers (2 mil)
thickness, and each from Bischof and Klein GmbH. The examples were
processed by coating one face of the polycarbonate film with the
coating composition to a thickness of 2 to 4 micrometers,
initiating the crosslinking of the coating composition using heat
and UV exposure (70.degree. C. for 30 seconds, 500 mJ/cm.sup.2
exposure using a metal halide UV lamp, operating at a wavelength of
about 290 to about 405 nm), and laminating all layers at a pressure
of up to 0.41 MPa.
[0104] Comparative Examples 1-8. All laminates for the comparative
examples were prepared using bisphenol-A polycarbonate films of 250
and 380 micrometers thickness, with a first protective layer of Tru
Cling.RTM. clear polyethylene masking (Tredegar Corp.) applied to
one side. The other, exposed face of the polycarbonate film was
coated with the coating composition described in Table 1 (above),
and a second protective layer as described in Table 2 (below)
laminated thereto. The films used for the second protective layer
include: Tru Cling.RTM. clear polyethylene masking ("Tru Cling.RTM.
Clear," Tredegar Corp.) for Comparative Examples 1 and 5; Tru
Cling.RTM. Blue polyethylene masking ("Tru Cling.RTM. Blue,"
Tredegar Corp.) for Comparative Examples 2 and 6; GHX 173
polyethylene film ("GHX 173", Bischof and Klein) for Comparative
Examples 3 and 7; and CoEx 375 polyethylene film ("CoEx 375",
Novacel, Inc.) for Comparative Examples 4 and 8.
[0105] The comparative examples were processed by applying the
coating composition to the polycarbonate film to a thickness of 2
to 4 micrometers, initiating the crosslinking of the coating
composition using heat and UV exposure 70.degree. C. for 30
seconds, 500 mJ/cm.sup.2 exposure using a metal halide UV lamp
operating at a wavelength of about 290 to about 405 nm, and
laminating all layers together by applying pressures up to 0.41 MPa
(60 psi).
[0106] Curl measurements. The laminates were measured for baseline
curl with (initial 2S mask, Table 2) the first protective layer of
Tru Cling.RTM. clear polyethylene film present. The first
protective layer was then removed, and the baseline curl was
re-measured (initial 1S mask, Table 2). The laminates without the
first protective layer were then processed additionally using one
of two scenarios. In Scenario 1, the laminates were processed
thermally, at 65.degree. C. for 30 minutes, 90.degree. C. for 4
minutes and 65.degree. C. for 120 minutes, with about 15 minutes of
cooling to room temperature between each temperature. In Scenario
2, a combination of thermal and UV treatments was used on the
laminates, at 65 to 70.degree. C. for 6 minutes, and 90.degree. C.
for 4 minutes with about 15 minutes of cooling between stages, and
500 mJ/cm.sup.2 exposure using a metal halide UV lamp operating at
a wavelength of about 290 to about 405 nm. The results of the curl
tests are shown in Table 2, below.
[0107] Peel strength measurements. The laminates without the first
protective layer present (initial 1S mask, Table 2) were measured
for initial peel strength at room temperature. These laminates
were. In scenario 1, the laminates were processed thermally, at
65.degree. C. for 30 minutes, 90.degree. C. for 4 minutes and
65.degree. C. for 120 minutes, with about 15 minutes of cooling to
room temperature between each temperature. In scenario 2, a
combination of thermal and UV treatments was used on the laminates,
at 65 to 70.degree. C. for 6 minutes, and 90.degree. C. for 4
minutes with about 15 minutes cooling to room temperature between
temperatures, and 500 mJ/cm.sup.2 exposure using a metal halide UV
lamp operating at a wavelength of about 290 to about 405 nm. The
results of the curl tests are shown in Table 2, below.
TABLE-US-00002 TABLE 2 PC film Curl (cm)* Pull Peel (cN/cm)** Gauge
Initial 2S Initial 1S Initial 1S Ex. No. Conditions (.mu.m) Mask
Mask Scenario 1 Scenario 2 Mask Scenario 1 Scenario 2 Comp1 Tru
Cling .RTM. Clear PE 380 0.28 0.03 0.48 0.58 0.66 0.66 0.66 Comp2
Tru Cling .RTM. Blue PE 380 0.33 0.08 0.51 0.48 0.66 0.88 0.66
Comp3 GHX 173 380 0.25 0 0.25 0.74 0.99 0.44 0.55 Ex. 1 GHX 173 R
380 0.08 0 0.74 0.66 17.1 11.1 14.8 Ex. 2 GHX 174 A 380 0 0 0.58
0.63 5.03 4.41 5.35 Comp. 4 CoEx 375 380 0 0 2.26 2.03 6.46 37.9
98.5 Comp. 5 Tru Cling .RTM. Clear PE 250 0.13 0 1.47 1.19 0.66
0.66 0.66 Comp. 6 Tru Cling .RTM. Blue PE 250 0.10 0.05 1.55 1.42
0.88 0.55 0.88 Comp. 7 GHX 173 250 0.05 0 2.41 2.57 0.99 0.66 0.66
Ex 3 GHX 173 R 250 0 0 2.41 2.34 3.61 2.52 3.51 Ex 4 GHX 174 A 250
0 0 2.37 2.41 4.93 5.40 5.90 Comp 8 CoEx 375 250 0 0 3.07 3.66 4.71
30.9 45.0 *Curl measurements represent averaged values of a set of
replicates. For curl measurements for each initial mask 2S and 1S,
no. of replicates n = 3; For curl data after exposure by Scenarios
1 and 2, n = 21, except for Comparative Examples 4 and 8, where n =
10. **Peel strength measurements represent values of a set of
replicates. For both initial peel strength measurement and for peel
strength after Scenarios 1 and 2, n = 6.
[0108] Evaluation of the laminates above using at both 250 and 380
micrometer (10 and 15 mil) thickness of the PC substrates for curl
showed the lowest curl is generally obtained with the thicker film
(Examples 1 and 2, and Comparative Examples 1-4). Of these, there
is less variation in curl when the Scenario 2 cure is used. The
lowest overall curl is seen in the Comparative Examples 1-3, 5, and
6; an intermediate amount of curl for Comparative Examples 3, 7,
and Examples 1-4; and significant curl for Comparative Examples 4
and 8. Of Examples 1-4, the best curl performance (at a PC film
thickness of 380 micrometers) is obtained with GHX 174 A (Example
2). In this test, Comparative Examples 4 and 8, which represent the
current manufacturing process and materials set, showed significant
curl across the two manufacturing scenarios.
[0109] Peel strength evaluation of Examples 1-4 showed consistent,
desirable values, across both manufacturing scenarios 1 and 2. For
380 micrometer thick polycarbonate film, the peel strength values
for both scenarios 1 and 2 for the GHX 173 R film (Example 1) are
higher than the corresponding peel strength values for GHX 174 A
film (Example 2). For 250 micrometer thick polycarbonate film
however, the peel strength values for both scenarios 1 and 2 for
the GHX 173 R film (Example 3) are lower than the corresponding
peel strength values for GHX 174 A film (Example 2). As seen in the
above data, GHX 174 A film showed greater consistency in peel
strength values for both polycarbonate film thicknesses tested (380
and 250 micrometers thickness, with an overall range of 4.41 to
5.90 cN/cm for both thicknesses) than did the GHX 173 R film, which
showed a higher range of peel strengths in combination with the 380
micrometer thick polycarbonate film (11.1 to 17.1 cN/cm), and a
lower range of peel strengths in combination with the 250
micrometer thick polycarbonate film (2.52 to 3.61 cN/cm).
[0110] Both Scenarios 1 and 2 gave useful peel strengths for both
GHX 173 R and GHX 174 A films. For the GHX 173 R films, thermal
treatment alone (Scenario 1, Table 2) showed a loss of peel
strength of 35% for Example 1, and a loss of peel strength of 30%
for Example 2. UV and thermal treatment (Scenario 2) showed loss of
peel strength of 13.5% for Example 1 and loss of peel strength of
2.8% for Example 2. For the GHX 174 A films, thermal treatment
alone (Scenario 1, Table 2) showed a loss of peel strength of 12.3%
for Example 2, and an increase in peel strength of 9.5% for Example
4. Also for GHX 174 A films, UV and thermal treatment (Scenario 2)
showed increases in peel strength of 6.4% for Example 2 and 19.7%
for Example 4.
[0111] By comparison, Comparative Examples 1-3 and 5-7 showed
relatively consistent but low peel strength below a useful value,
and hence low adhesion across both manufacturing Scenarios 1 and 2
during treatment. This resulted in adhesion failure by
delamination, which in turn gave an unacceptable damaged product,
low product quality, low process yields and jamming of processing
and handling equipment. Comparative Examples 4 and 8, showed an
opposite trend, having too high an adhesion level which is
magnified by exposure to thermal ovens and in particular UV
irradiation. Peel strength for Comparative Example 4 increased by
586% when processed under Scenario 1, and increased by 1,525% when
processed under Scenario 2. Similarly, peel strength for
Comparative Example 8 increased by 656% when processed under
scenario 1, and increased by 956% when processed under scenario 2,
making manual removal of the protective film difficult without
damaging the polycarbonate printed substrate or the use of a
cleaning solvent.
[0112] Compounds are described herein using standard nomenclature.
A dash ("-") that is not between two letters or symbols is used to
indicate a point of attachment for a substituent. For example,
--CHO is attached through the carbon of the carbonyl (C.dbd.O)
group. The singular forms "a," "an," and "the" include plural
referents unless the context clearly dictates otherwise. The
endpoints of all ranges reciting the same characteristic or
component are independently combinable and inclusive of the recited
endpoint. All references are incorporated herein by reference. The
terms "first," "second," and the like herein do not denote any
order, quantity, or importance, but rather are used to distinguish
one element from another.
[0113] While typical embodiments have been set forth for the
purpose of illustration, the foregoing descriptions should not be
deemed to be a limitation on the scope herein. Accordingly, various
modifications, adaptations, and alternatives may occur to one
skilled in the art without departing from the spirit and scope
herein.
* * * * *